Light emitting device

ABSTRACT

Disclosed herein is a light emitting device manufactured by separating a growth substrate in a wafer level. The light emitting device includes: a base; a light emitting structure disposed on the base; and a plurality of second contact electrodes disposed between the base and the light emitting structure, wherein the base includes at least two bulk electrodes electrically connected to the light emitting structure and an insulation support disposed between the bulk electrodes and enclosing the bulk electrodes, the insulation support and the bulk electrodes each including concave parts and convex parts engaged with each other on surfaces facing each other, and the convex parts including a section in which a width thereof is changed in a protrusion direction.

PRIORITY CLAIMS AND CROSS-REFERENCE TO RELATED APPLICATION

This patent document claims priorities and benefits of Korean PatentApplication No. 10-2014-0076410, filed on Jun. 23, 2014, Korean PatentApplication No. 10-2014-0098363, filed on Jul. 31, 2014, Korean PatentApplication No. 10-2015-0012864, filed on Jan. 27, 2015, and KoreanPatent Application No. 10-2015-0076527, filed on May 29, 2015, thecontents of which are incorporated by reference herein in its entirety.

TECHNICAL FIELD

The disclosure of this patent document relates to a light emittingdevice. Some implementations of the disclosed technology relate to thelight emitting device manufactured by separating a growth substrate in awafer level.

BACKGROUND

A light emitting device, which is an inorganic semiconductor deviceemitting light by recombination between electrons and holes, has beenrecently used in several fields such as a display, a vehicle lamp, ageneral illuminating device, and the like.

Recently, in accordance with an increase in a demand for a small highoutput light emitting device, a demand for a large-area flip-chip typelight emitting device having excellent heat radiation efficiency hasincreased. Electrodes of the flip-chip type light emitting device aredirectly bonded to a secondary substrate, and a wire for supplyingexternal power to the flip-chip type light emitting device is not used,such that the flip-chip type light emitting device has heat radiationefficiency significantly higher than that of a horizontal type lightemitting device. Therefore, even though a high density current isapplied, heat can be effectively conducted to the secondary substrate,such that the flip-chip type light emitting device is appropriate for ahigh output light source.

SUMMARY

Exemplary embodiments of the present disclosure provide a light emittingdevice capable of having improved light efficiency and heat radiationefficiency by separating a growth substrate.

Exemplary embodiments of the present disclosure provide a light emittingdevice including a support member on which pads are formed whilesubstituting for a secondary substrate in a wafer level.

Exemplary embodiments of the present disclosure provide a light emittingdevice capable of improving a heat radiation effect and preventing ashort circuit between pads by securing widths of the pads as wide aspossible.

Exemplary embodiments of the present disclosure provide a light emittingdevice capable of being directly mounted on a printed circuit board, orthe like, using a solder paste by preventing diffusion of a metallicelement in the solder paste.

Exemplary embodiments of the present disclosure provide a light emittingdevice capable of decreasing the possibility of a failure by havingexcellent mechanical stability.

According to one aspect of the present disclosure, there is provided alight emitting device including: a light emitting structure including afirst conductive type semiconductor layer, a second conductive typesemiconductor layer, and an active layer disposed between the firstconductive type semiconductor layer and the second conductive typesemiconductor layer; first and second contact electrodes disposed on orover the light emitting structure, each ohmic-contacting the first andsecond conductive type semiconductor layers; an insulating layerinsulating the first and second contact electrodes from each other andat least partially covering the first and second contact electrodes; astress buffering layer disposed on or over the insulating layer; firstand second bulk electrodes disposed on or over the light emittingstructure and the stress buffering layer, the first and second bulkelectrodes electrically connected to the first and second contactelectrodes; and an insulation support covering side surfaces of thefirst and second bulk electrodes and at least partially exposing uppersurfaces of the first and second bulk electrodes, wherein the first bulkelectrode includes a protrusion part protruding from a side surface ofthe first bulk electrode toward the second bulk electrode, and thesecond bulk electrode includes a concave part depressed from a sidesurface of the second bulk electrode.

In some implementations, the protrusion part can be engaged with theconcave part.

In some implementations, the protrusion part has a varying width fromthe side surface of the first bulk electrode to a surface of theprotrusion part.

In some implementations, the concave part has a varying width from theside surface of the second bulk electrode to a surface of the concavepart.

In some implementations, the first bulk electrode includes one or moreadditional protrusion part and the second bluk electrode includes one ormore additional concave parts, and the one or more additional protrusionparts are engaged with the one or more additional concave parts.

In some implementations, the insulating layer can include first andsecond insulating layers, the first insulating layer can partially coverthe second contact electrode and include first and second opening partseach partially exposing the first conductive type semiconductor layerand the second contact electrode, the first contact electrode canpartially cover the first insulating layer, and the second insulatinglayer can partially cover the first contact electrode and includes thirdand fourth opening parts each partially exposing the first and secondcontact electrodes.

In some implementations, the light emitting device can further include aconnecting electrode disposed between the second contact electrode andthe second bulk electrode, wherein the connecting electrode includes thesame material as that of the first contact electrode.

In some implementations, a portion of the first insulating layer can beinterposed between the first and second contact electrodes.

In some implementations, the light emitting device can further include aconnecting electrode disposed on or over the second contact electrode,wherein the insulating layer includes first and second opening partseach exposing the first contact electrode and the connecting electrode.

In some implementations, the light emitting structure is disposed topartially expose the first conductive type semiconductor layer, and thefirst contact electrode can be disposed over the exposed firstconductive type semiconductor layer.

In some implementations, the light emitting structure is disposed toform a plurality of holes partially exposing the first conductive typesemiconductor layer, and the first contact electrode can be electricallyconnected to the first conductive type semiconductor layer through theplurality of holes.

In some implementations, the light emitting device can further includefirst and second pad electrodes disposed on or over the first and secondbulk electrodes, respectively, wherein the insulation support coversportions of the upper surfaces of the first and second bulk electrodesand surrounds side surfaces of the first and second pad electrodes.

In some implementations, the first pad electrode cannot be disposed onor over the protrusion part.

In some implementations, the first and second pad electrodes can havesubstantially the same surface area.

In some implementations, the light emitting device can further include awavelength converting unit disposed on or over a lower surface of thelight emitting structure.

In some implementations, the first and second bulk electrodes are spacedby a substantially constant distance.

In some implementations, the first bulk electrode has an area greaterthan that of the second bulk electrode.

In some implementations, the first bulk electrode can include additionalprotrusion part protruding from the protrusion part, and the second bulkelectrode can include additional concave part depressed from the concavepart.

In some implementations, the additional protrusion part overlaps with acentral portion of the light emitting device in a vertical direction.

In some implementations, the additional protrusion part has a shapeincluding at least a portion of a polygon, a circle, or an ellipsehaving an inscribed circle having center located at a central portion ofthe light emitting device and diameter of about 50 μm or more.

According to another aspect of the present disclosure, there is provideda light emitting device including: a light emitting structure includinga first conductive type semiconductor layer, a second conductive typesemiconductor layer, and an active layer disposed between the firstconductive type semiconductor layer and the second conductive typesemiconductor layer; first and second contact electrodes disposed on orover the light emitting structure, the first and second contactelectrodes ohmic-contacting the first and second conductive typesemiconductor layers; an insulating layer insulating the first andsecond contact electrodes from each other and at least partiallycovering the first and second contact electrodes; first and second bulkelectrodes disposed on or over the light emitting structure and theinsulating layer, the first and second bulk electrodes electricallyconnected to the first and second contact electrodes; and an insulationsupport covering side surfaces of the first and second bulk electrodesand at least partially exposing upper surfaces of the first and secondbulk electrodes, wherein the first and the second bluk electrodes arearranged to face each other and form a virtual line along a spacedregion between the first and second bulk electrodes, the virtual linehaving a bending portion, and the first bulk electrode has an areagreater than that of the second bulk electrode.

In some implementations, a starting point and an ending point of thevirtual line can be disposed on or over the same line.

According to still another aspect of the present disclosure, there isprovided a light emitting device including: a light emitting structureincluding a first conductive type semiconductor layer, a secondconductive type semiconductor layer, and an active layer disposedbetween the first conductive type semiconductor layer and the secondconductive type semiconductor layer; first and second contact electrodesdisposed on or over the light emitting structure, the first and secondcontact electrodes ohmic-contacting the first and second conductive typesemiconductor layers; an insulating layer insulating the first andsecond contact electrodes from each other and at least partiallycovering the first and second contact electrodes; first and second bulkelectrodes disposed on or over the insulating layer, the first andsecond bulk electrodes electrically connected to the first and secondcontact electrodes, respectively; and an insulation support coveringside surfaces of the first and second bulk electrodes and at leastpartially exposing upper surfaces of the first and second bulkelectrodes, wherein the first bulk electrode includes a first protrusionpart protruding from a side surface of the first bulk electrode towardthe second bulk electrode and a second protrusion part protruding fromthe first protrusion part, the second bulk electrode includes a firstconcave part depressed from a side surface of the second bulk electrodeand a second concave part further depressed from the first concave part,and the second protrusion part is shaped to include at least a portionof a polygon, a circle, or an ellipse having an inscribed circle with acenter located at a central portion of the light emitting device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a light emitting device according tothe related art.

FIG. 2(a) to FIG. 13(b) are plan views and cross-sectional views of anexemplary light emitting device according to some embodiments.

FIG. 14(a) is a cross-sectional view of an exemplary light emittingdevice according to some embodiments.

FIG. 14(b) is a perspective view of an exemplary light emitting devicepackage according to some embodiments.

FIGS. 15(a) to 15(f) are cross-sectional views and a plan view of anexemplary light emitting devices according to some embodiments.

FIGS. 16 and 17 are, respectively, a plan view and a cross-sectionalview for describing an exemplary light emitting device according to someembodiments.

FIGS. 18(a) to 18(d) are plan views of exemplary light emitting devicesaccording to some embodiments.

FIGS. 19 and 20 are, respectively, a plan view and a cross-sectionalview of an exemplary light emitting device according to someembodiments.

FIGS. 21 and 22 are, respectively, a plan view and a cross-sectionalview for describing an exemplary light emitting device according to someembodiments.

FIGS. 23(a), 23(b) and FIG. 24 show plan views and a cross-sectionalview for describing an exemplary light emitting device according to someembodiments.

FIG. 25(a) to FIG. 40(b) are plan views and cross-sectional views fordescribing exemplary light emitting devices according to someembodiments.

FIG. 41 shows an exploded perspective view of an exemplary lightingapparatus to which a light emitting device according to some embodimentsof the present disclosure is applied.

FIG. 42 shows a sectional view of an exemplary display device to which alight emitting device according to some embodiments of the presentdisclosure is applied.

FIG. 43 shows a sectional view of an exemplary display device to which alight emitting device according to some embodiments of the presentdisclosure is applied.

FIG. 44 shows a sectional view of an exemplary headlight to which alight emitting device according to some embodiments of the presentdisclosure is applied.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the disclosed technology will bedescribed in detail with reference to the accompanying drawings.Exemplary embodiments to be provided below are provided by way ofexample to facilitate the understanding of exemplary implementations ofthe disclosed technology. Therefore, the disclosed technology is notlimited to exemplary embodiments to be described below, but can beimplemented in other forms. In addition, in the accompanying drawings,widths, lengths, thicknesses, and the like, of components can beexaggerated for convenience. In addition, it will be understood thatwhen one component is referred to as being “on”, “over” or “above”another component, one component can be “directly on”, “directly over”or “directly above” another component or can have the other componentinterposed therebetween. Like reference numerals denote like componentsthroughout the present specification.

FIG. 1 illustrates a flip-chip type light emitting device according tothe related art. The flip-chip type light emitting device 100 accordingto the related art as illustrated in FIG. 1 can include a growthsubstrate 11, a first conductive type semiconductor layer 13, an activelayer 15, a second conductive type semiconductor layer 17, a firstelectrode 19, a second electrode 20, a first pad 30 a, a second pad 30b, and an insulating layer 31. A light emitting cell can be formed toinclude the first conductive type semiconductor layer 13, the activelayer 15, and the second conductive type semiconductor layer 17. Thefirst conductive type semiconductor layer 13 and the second conductivetype semiconductor layer 17 can be electrically connected to the firstpad 30 a and the second pad 30 b, respectively.

In the flip-chip type light emitting device according to the relatedart, the growth substrate 11 is separated from the first conductive typesemiconductor layer 13, thereby making it possible to improve heatradiation efficiency and light efficiency of the light emitting diode.

However, in the case in which the growth substrate 11 is removed, thefirst pad 30 a and the second pad 30 b of the flip-chip type lightemitting device are separated from each other, and a support membersupporting the semiconductor layers 13, 15, and 17 is not present. Thus,the semiconductor layers 13, 15, and 17 are fragile.

In the related art, a technology of attaching a secondary substrate tothe semiconductor layers and then thinning or separating the growthsubstrate using a chemical etching technology or a laser lift-offtechnology has been well known. However, since the secondary substrateshould be separately attached to the semiconductor layers, amanufacturing cost is increased. Therefore, a technology capable ofpreventing cracks of the semiconductor layers generated in the case ofthinning or separating the growth substrate has been demanded.

Meanwhile, in the flip-chip type light emitting device, the first bump30 a and the second bump 30 b are used as heat radiating paths.Therefore, it is advantageous in radiating heat of the light emittingdevice to secure widths of the first bump 30 a and the second bump 30 bas great as possible. However, in the flip-chip type light emittingdevice, since the electrodes 19 are formed by removing a predeterminedregion, the first and second bumps 30 a and 30 b are disposed to bespaced apart from each other by a predetermined distance. In addition,the widths of the first and second bumps 30 a and 30 b are limited to beconstant in order to prevent a short circuit between the bumps, which isdisadvantageous in radiating heat of the light emitting device.

Meanwhile, a technology of manufacturing a light emitting device moduleby allowing the pads of the light emitting device to directly adhereonto a printed circuit board, or the like, using a solder paste has beenrecently studied. For example, the light emitting device module can bemanufactured by directly mounting a light emitting device chip on theprinted circuit board without packaging the light emitting device chipor can be manufactured by manufacturing a wafer level light emittingdevice package and mounting the wafer level light emitting devicepackage on the printed circuit board. In the case of these lightemitting device modules, since the pads directly contact the solderpaste, a metallic element such as tin (Sn), or the like, in the solderpaste is diffused into the light emitting device, such that anelectrical short circuit can be generated in the light emitting deviceto cause a diode defect.

In addition, a demand for a chip scale package in which a process ofpackaging the light emitting device in a separate housing, or the like,is omitted and the light emitting device itself is used as a package inorder to miniaturize the light emitting device and increase an output ofthe light emitting device has increased. Particularly, the electrode ofthe flip-chip type light emitting device can perform a function similarto that of a lead of the package, such that the flip-chip type lightemitting device can also be usefully used in the chip scale package.

In the case in which a device having a form of the chip scale package isused as a high output light emitting apparatus, a high density currentis applied to the chip scale package. When the high density current isapplied, heat generated from the light emitting chip is also increased.This heat generates thermal stress in the light emitting device, andgenerates stress on an interface between materials having differentcoefficients of thermal expansion to generate residual stress.

Particularly, when a crack is generated between the electrodes by thestress, it is likely that a failure of the light emitting device will begenerated, which causes a defect of the light emitting device.Therefore, the light emitting device used in the high output lightemitting apparatus requires high heat radiation efficiency and excellentmechanical stability.

FIG. 2 to FIG. 13(b) are plan views and cross-sectional views fordescribing an exemplary light emitting device and an exemplary method ofmanufacturing the same according to some embodiments.

FIG. 2(a) is a plan view of a growth substrate on which second contactelectrodes are formed on an epitaxial layer, and FIG. 2(b) is across-sectional view taken along line A-A of FIG. 2(a).

Referring to FIG. 2, a growth substrate 110 is first prepared, and alight emitting structure 120 is formed on the growth substrate 110. Thegrowth substrate 110 can be any substrate on which the light emittingstructure 120 can be grown, and can include, for example, a sapphiresubstrate, a silicon substrate, a silicon carbide substrate, a spinelsubstrate, a nitride substrate, or the like. For example, in the presentexemplary embodiment, the growth substrate 110 can be the sapphiresubstrate.

Meanwhile, in the case in which the growth substrate 110 and the lightemitting structure 120 that is to be grown on the growth substrate 110have heterogeneous characteristics, for example, in the case in whichthe light emitting structure 120 includes a nitride based semiconductorand the growth substrate 110 is a heterogeneous material substrate suchas the sapphire substrate, a buffer layer (not illustrated) can befurther formed on the growth substrate 110.

In addition, the growth substrate 110 can have various growth surfaces,for example, a polar growth surface such as a c surface ((0001)), anon-polar growth surface such as an m surface ((1-100)) or an a surface((11-20)), or a semi-polar growth surface such as a (20-21) surface. Inaddition, the growth substrate 110 can be a patterned substrate.

A first conductive type semiconductor layer 121, an active layer 123,and a second conductive type semiconductor layer 125 are grown on thegrowth substrate 110.

The first conductive type semiconductor layer 121 can include, forexample, an n-type gallium nitride based semiconductor layer, and thesecond conductive type semiconductor layer 125 can include a p-typegallium nitride based semiconductor layer. In addition, the active layer123 can have a single quantum well structure or a multi-quantum wellstructure and include a well layer and a barrier layer. In addition, thewell layer can include a composite element selected depending on awavelength of required light, for example, InGaN.

The first conductive type semiconductor layer 121 and the secondconductive type semiconductor layer 125 can be semiconductor layershaving different conductive types, and the semiconductor layers 121,123, and 125 can be formed by various deposition and growth methodsincluding metal organic chemical vapor deposition (MOCVD), molecularbeam epitaxy (MBE), or hydride vapor phase epitaxy (HVPE), and the like.

Hereinafter, a description for the well-known technology for thesemiconductor layers will be omitted.

Then, second contact electrodes 130 can be formed using a lift-offtechnology. The second contact electrode 130 can include a reflectinglayer 131 and a cover layer 133. In addition, the second contactelectrode 130 can further include a stress relaxing layer (notillustrated) disposed between the reflecting layer 131 and the coverlayer 133. The stress relaxing layer relaxes stress due to a differencebetween coefficients of thermal expansion of the reflecting layer 131and the cover layer 133.

The reflecting layer 131 can be formed of or include, for example,Ni/Ag/Ni/Au, and can have an entire thickness of about 1600 Å. Thereflecting layer 131 can be formed to have a shape in which sidesurfaces thereof are inclined, for example, a bottom part thereof isrelatively greater. The reflecting layer 131 can be formed using e-beamevaporation.

Meanwhile, the cover layer 133 covers an upper surface and the sidesurfaces of the reflecting layer 131 to protect the reflecting layer131. The cover layer 133 can be formed using a sputtering technology orusing e-beam evaporation (for example, planetary e-beam evaporation) ofperforming vacuum deposition while rotating the growth substrate 110 ina state in which the growth substrate 110 is inclined. The cover layer133 can include Ni, Pt, Ti, or Cr, and be formed by depositing, forexample, about five pairs of Ni/Pt or about five pairs of Ni/Ti. In someimplementations, the cover layer 133 can include TiW, W, or Mo.

The stress relaxing layer can be variously selected depending on metalmaterials of the reflecting layer 131 and the cover layer 133. Forexample, in the case in which the reflecting layer 131 is made of orincludes Al or an Al alloy and the cover layer 133 is made of orincludes W, TiW, or Mo, the stress relaxing layer can be a single layerof Ag, Cu, Ni, Pt, Ti, Rh, Pd, or Cr or a composite layer of Cu, Ni, Pt,Ti, Rh, Pd, or Au. In addition, in the case in which the reflectinglayer 131 is made of or includes Al or an Al alloy and the cover layer32 is made of or includes Cr, Pt, Rh, Pd, or Ni, the stress relaxinglayer can be a single layer Ag or Cu or a composite layer of Ni, Au, Cu,or Ag.

In addition, the second contact electrode 130 can further include anoxidation preventing metal part (not illustrated). The oxidationpreventing metal part can cover the cover layer 133, include Au in orderto prevent oxidation of the cover layer 133, and can be formed of orinclude, for example, Au/Ni or Au/Ti. In some implementations, Ti ispreferred since adhesion of an oxidized layer such as SiO₂ is good. Theoxidation preventing metal part can also be formed using a sputteringtechnology or using e-beam evaporation (for example, planetary e-beamevaporation) of performing vacuum deposition while rotating the growthsubstrate 110 in a state in which the growth substrate 110 is inclined.

After the second contact electrodes 130 are formed, a photo-resistpattern is removed, such that the second contact electrodes 130 areformed on the second conductive type semiconductor layer 125, asillustrated in FIG. 2(a) or 2(b).

FIGS. 2(a) and 2(b) illustrate partial regions of a wafer before thewafer is divided. The partial regions of the wafer can be or includeindividual device regions in which the light emitting device accordingto the present disclosure is to be manufactured. In this case, regionsin which the second contact electrodes 130 are not formed in both distalends of the growth substrate 110 and the light emitting structure 120can be division scheduled regions for dividing the wafer. Drawings fordescribing the present exemplary embodiment to be described below can bedrawings for describing the individual device regions unless separatelydescribed.

FIG. 3(a) is a plan view of the growth substrate on which mesas areformed, and FIG. 3(b) is a cross-sectional view taken along line A-A ofFIG. 3(a).

Referring to FIG. 3, mesas M are formed on a first conductive typesemiconductor layer 121. The mesa M includes an active layer 123 and asecond conductive type semiconductor layer 125. The active layer 123 isdisposed between the first conductive type semiconductor layer 121 andthe second conductive type semiconductor layer 125. Meanwhile, secondcontact electrodes 130 are disposed on the mesas M.

The mesa M can be formed by patterning the second conductive typesemiconductor layer 125 and the active layer 123 so that the firstconductive type semiconductor layer 121 is exposed. Side surfaces of themesa M can be formed to be inclined using a technology such as aphoto-resist reflow technology. Profiles of the inclined side surfacesof the mesa M can improve extracting efficiency of light generated inthe active layer 123.

A plurality of mesas M can have a long shape in which they are extendedin parallel with each other in one side direction, as illustrated. Inaddition, due to the plurality of mesas M, basin part regions B can beformed between the mesas M. The basin part regions B can be regionsdefined by mesas M disposed at both sides thereof and exposing the firstconductive type semiconductor layer 121.

Meanwhile, the second contact electrodes 130 cover most of the uppersurfaces of each of the mesas M, and have substantially the same shapeas a plane shape of the mesa M. An entire area of upper surfaces of thesecond contact electrodes 130 can be 70%, 80%, or 90% or more of an areaof an upper surface of the growth substrate 110 or an area of a lowersurface of the first conductive type semiconductor layer 121.

FIG. 4(a) is a plan view of the growth substrate on which first contactelectrodes are disposed in the basin part regions, and FIG. 4(b) is across-sectional view taken along line A-A of FIG. 4(a).

Referring to FIGS. 4(a) and 4(b), the first contact electrodes 140 canbe formed in the basin part regions, which are regions between the mesasM. The first contact electrodes 140 can be formed using deposition andlift-off technologies. The first contact electrode 140 can include ametal, for example, at least one of Ni, Pt, Pd, Rh, W, Ti, Cr, Al, Ag,or Au. The first contact electrode 140 can ohmic-contact the firstconductive type semiconductor layer 121, and can include a reflectinglayer made of or including a metal having high reflectivity, similar tothe second contact electrode 130 described above.

The first contact electrodes 140 can have a long shape in which they areextended in parallel with each other in one side direction, asillustrated. In addition, the first contact electrodes 140 can have ashape in which they are extended in parallel with each other while beingspaced apart from the second contact electrodes 130 by a predeterminedinterval.

FIG. 5(a) is a plan view of the growth substrate on which a firstinsulating layer is formed on the second contact electrodes and thefirst contact electrodes, and FIG. 5(b) is a cross-sectional view takenalong line A-A of FIG. 5(a).

Referring to FIG. 5, the second contact electrodes 130 and the firstcontact electrodes 140 are covered with the first insulating layer 150.Then, portions of the first insulating layer 140 are removed to expose alower region. The first insulating layer 150 can include a plurality offirst opening regions 150 a exposing portions of the second contactelectrodes 130 and a plurality of second opening regions 150 b exposingportions of the first contact electrodes 140. The plurality of firstopening regions 150 a can be disposed to be spaced apart from each otherby a predetermined distance, respectively. The plurality of secondopening regions 150 b can be disposed to be spaced apart from each otherby a predetermined distance, respectively. Each of the plurality offirst opening regions 150 a and each of the plurality of second openingregions 150 b can be disposed to be spaced apart from each other by apredetermined distance. The above-mentioned predetermined distances canbe determined in consideration of current diffusion of the lightemitting device according to the exemplary embodiment of the presentdisclosure. In addition, the first opening regions 150 a can bepositioned to be biased toward the same end portions of the mesas.

Predetermined areas of each of the first opening regions 150 a and eachof the second opening regions 150 b can be opened or exposed inconsideration of areas of the second contact electrodes 130 and thefirst contact electrodes 140 disposed below the first opening regions150 a and the second opening regions 150 b. The first insulating layer150 can be formed with a uniform thickness or be formed with differentthicknesses depending on regions in which it is disposed.

The first insulating layer 150 can include an insulating material andcan be formed of or include, for example, an oxide layer of SiO₂, or thelike, a nitride layer of SiN_(x) or the like, or an insulating layer ofMgF₂. Further, the first insulating layer 150 can include multiplelayers, and include a distributed Bragg reflector in which materialshaving different refractive indices are alternately stacked. Forexample, layers made of or including SiO₂/TiO₂, or SiO₂/Nb₂O₅, or thelike, are stacked, thereby making it possible to form an insulatingreflecting layer having high reflectivity.

The first insulating layer 150 can be formed using a technology such aschemical vapor deposition (CVD), or the like, and be then patterned toform the first opening regions 150 a and the second opening regions 150b.

FIG. 6(a) is a plan view of the first insulating layer on which padmetal layers are formed, and FIG. 6(b) is a cross-sectional view takenalong line A-A of FIG. 6(a).

Referring to FIG. 6(a), a plurality of pad metal layers 160 are formedon the first insulating layer 150. The pad metal layers 160 can bedisposed in the first and second opening regions 150 a and 150 bexposing portions of the second contact electrodes 130 and the firstcontact electrodes 140. The pad metal layers 160 are formed oversubstantially the entire region of the growth substrate 110 except forspaces therebetween. Therefore, a current can be easily dispersedthrough the pad metal layers 160. The pad metal layers 160 canohmic-contact the second contact electrodes 130 and the first contactelectrodes 140 through the first and second opening regions 150 a and150 b.

The pad metal layer 160 can include an adhering layer, a metalreflecting layer, a diffusion preventing layer, and a seed layer. Theadhering layer can include Ti, Cr, Ni, or Ta, or a combination thereof,and can be used in order to improve adhesion between the pad metal layer160 and the first insulating layer 150. The metal reflecting layer caninclude Al, or Ag, or a combination thereof, and reflects light incidentto the pad metal layer 160 to increase reflectivity of the lightemitting device. The diffusion preventing layer can include Cr, Ti, Ni,Mo, TiW, or W, or a combination thereof, and prevents diffusion of metalatoms to protect the metal reflecting layer. The seed layer, which is alayer formed in order deposit and plate a bulk electrode (notillustrated) formed in a subsequent process, can be formed of or includeAu or Cu. Therefore, the seed layer can be disposed at the uppermostportion of the pad metal layer 160. The pad metal layer 160 can beformed through a depositing process or an electroplating process. Thepad metal layer 160 can be formed at a uniform thickness or be formed atdifferent thicknesses depending on regions in which it is disposed. Anentire area of the pad metal layers 160 can be 70%, 80%, or 90% or moreof the area of the upper surface of the growth substrate 110 or the areaof the lower surface of the first conductive type semiconductor layer121.

FIG. 7 is a plan view of a partial region of a wafer before the lightemitting device according to the exemplary embodiment of the presentdisclosure is divided into individual diodes.

Referring to FIG. 7, the pad metal layers 160 and the first insulatinglayer 150 form stripe patterns. In FIG. 7, the first insulating layer150 is exposed between the pad metal layers 160 disposed in parallelwith each other. Here, dotted lines a can indicate division scheduledlines for dividing the wafer into the individual diodes. The divisionscheduled lines can be formed in the division scheduled regionsdescribed with reference to FIG. 2.

The pad metal layers 160 are divided into first and second metal layersalong the dotted lines a through a subsequent process, but are connectedto each other in the wafer, such that a current can flow therein in anelectroplating process.

FIGS. 8(a) and 8(b) are plan views of the pad metal layers on whichinsulation supports are formed, FIG. 9(a) is a cross-sectional viewtaken along line A-A of FIGS. 8(a) and 8(b), and FIG. 9(b) is across-sectional view taken along line B-B of FIGS. 8(a) and 8(b).

Referring to FIGS. 8(a), 8(b) and 9, the insulation supports 170 andbulk electrodes 180 are disposed on the pad metal layer 160. Theinsulation supports 170 include the bulk electrodes 180 formed ininternal regions thereof, and are coupled to the bulk electrodes 180through coupling regions 175, 175 a, and 175 b. In addition, supportparts 185 enclosing the insulation supports 170 can be further included.

A spaced distance between the bulk electrodes 175 can be 30 to 300 μm.Therefore, since the bulk electrodes 175 can be formed at widthsrelatively wider as compared with the related art, heat radiationefficiency of the light emitting device can be improved.

The insulation support 170 includes a coupling pattern formed in theinternal region thereof and enclosing the bulk electrode 180, and thebulk electrode 180 also includes a coupling pattern formed at an edgethereof and coupled to the coupling pattern of the insulation support170. The coupling pattern of the insulation support 170 and the couplingpattern of the bulk electrode 180 are coupled to each other, such thatcoupling regions 175, 175 a, and 175 b are formed. The coupling regions175 and 175 a can be formed in a reverse trapezoidal sawtooth pattern,as illustrated. In addition, although not illustrated, the couplingregions 175 and 175 a can be formed in a triangular sawtooth pattern, atrapezoidal sawtooth pattern, a rectangular sawtooth pattern, or thelike, in addition to the reverse trapezoidal sawtooth pattern.

When comparing FIG. 8(a) and FIG. 8(b) with each other, FIG. 8(a)includes a first coupling region 175 a and a second coupling region 175b. The first coupling region 175 a corresponds to the coupling region175 of FIG. 8(a). The second coupling region 175 b is disposed in aregion in which the bulk electrodes 180 face each other. The secondcoupling region 175 b includes patterns entering the bulk electrodes 180facing each other at a depth deeper as compared with the first couplingregion 175 a. In this case, each of the pad metal layers 160 disposedbelow the second coupling region 175 b is disposed so as not to beoverlapped with the second coupling region 175 b. That is, in the caseof an exemplary embodiment of FIG. 8(b), the second coupling region 175b is disposed on the first insulating layer 150 in order to prevent ashort circuit between the bulk electrodes 180 due to the second couplingregion 175 b. In an exemplary embodiment of FIG. 8(b), coupling forcebetween the bulk electrodes 180 facing each other and the insulationsupports 170 disposed between the bulk electrodes 180 can be enhanced.

Again referring to FIG. 8(b), the bulk electrodes 180 are engaged witheach other through convex parts and concave parts each included therein.The convex parts and the concave parts are disposed on surfaces on whichthe bulk electrodes 180 face each other. The convex parts includesections in which a width thereof becomes wide in a protrusiondirection, and although the case in which the width discontinuouslybecomes wide has been illustrated in the present exemplary embodiment,the present disclosure is not limited thereto, and other implementationsare also possible. Therefore, the width of the convex parts can alsocontinuously become wide in the protrusion direction. In the presentexemplary embodiment, in the case in which the width of the convex partsdiscontinuously becomes wide, the width of the convex parts can becomewide by 1.5 to 2 times.

A length L of FIG. 8(b) indicates a length of the convex parts in theprotrusion direction. A ratio of the entire area of the convex parts tothe entire area of the bulk electrodes 180 can be calculated through thelength L, and in the present exemplary embodiment, the entire area ofthe convex parts can be ¼ or more of the entire area of the bulkelectrodes 180. That is, since a ratio of an area in which the bulkelectrodes 180 according to the present exemplary embodiment are coupledto each other is significantly greater than that of FIG. 8(a), strongcoupling force between the bulk electrodes 180 can be secured.Meanwhile, the insulation supports 170 and the bulk electrodes 180 arecoupled to each other in the coupling region 175, thereby making itpossible to form a base included in the light emitting device accordingto the present disclosure.

Each of the coupling pattern of the insulation support 170 and thecoupling pattern of the bulk electrode 180 can include a plurality ofconcave parts and a plurality of convex parts, and the insulationsupport 170 and the bulk electrode 180 are engaged with each other likea saw-toothed wheel in the coupling region 175, as illustrated.

In the present disclosure, since the insulation support 170 and the bulkelectrode 180 are engaged with each other like the saw-toothed wheel,the bulk electrode 180 and the insulation support 170 can contact eachother while having a wider surface area, as compared with the case inwhich the coupling patterns are not present. Therefore, since a decreasein coupling force due to different coefficients of thermal expansionbetween the insulation support 170 and the bulk electrode 180 can beprevented, reliability of the light emitting device can be improved.

The convex parts of the coupling pattern of the insulation support 170and the convex parts of the coupling pattern of the bulk electrode 180adjacent to each other can be point-symmetrical to each other. That is,when the convex parts of the insulation support 170 and the convex partsof the bulk electrode 180 are rotated around one point between theconvex parts by 180 degrees, they can be overlapped with each other.

In addition, in order to enhance the coupling force between theinsulation support 170 and the bulk electrode 180, each of a protrusionpart of the coupling pattern of the insulation support 170 and aprotrusion part of the coupling pattern of the bulk electrode 180 caninclude regions in which a width thereof becomes wide in the protrusiondirection. Further, the width of each of the protrusion parts cancontinuously or discontinuously become wide in the protrusion direction.A form of each of the convex parts of the coupling pattern of theinsulation support 170 and the convex parts of the coupling pattern ofthe bulk electrode 180 can be used as a form of each of the protrusionparts without being limited as along as it is a form in which theinsulation support 170 and the bulk electrode 180 can be mechanicallycoupled to each other.

Meanwhile, the insulation support 170 is enclosed by the support part185. Through the support parts 185, structural stability of the lightemitting device during a process can be enhanced, and warpage, failure,and the like, of the light emitting structure 120 after the growthsubstrate 110 is removed can be prevented.

The insulation support 170 can include at least one of photosensitivepolyimide, Su-8, a photo-resist for plating, parylene, an epoxy moldingcompound (EMC), or a ceramic powder. The insulation supports 170 and thebulk electrodes 180 can have a height of 20 to 200 μm. In addition,upper surfaces of the insulation supports 170 and upper surfaces of thebulk electrodes 180 can be disposed to be flush with each other.

Since the base according to the present disclosure is provided byforming the bulk electrodes 180 and the insulation supports 170, thebase can have various thicknesses, if necessary. Therefore, since thethickness of the base according to the present disclosure can besubstantially similar to that of a metal substrate according to therelated art, the light emitting device manufactured according to thepresent disclosure can be similarly applied to applications according tothe related art.

In order to form the bulk electrodes 180 in the internal regions of theinsulation supports 170, the insulation supports 170 covering the padmetal layers 160 and the first insulating layer 150 are first formedthrough application and hardening. Then, portions of the insulationsupports 170, for example, portions of the internal regions of theinsulation supports 170 are removed to form internal opening regionsexposing portions of the pad metal layers 160. At the time of formingthe internal opening regions, the insulation supports 170 can bepatterned through exposure and development processes, and the couplingpatterns can be formed in the internal region of the insulation support170 through the patterning.

Next, the bulk electrodes 180 buried in the internal opening regions areformed. The bulk electrodes 180 can be formed through a method such as adepositing method, or a plating method, or the like. The bulk electrodes180 are formed to be filled in the internal opening regions to contactthe pad metal layer 160, such that the bulk electrodes 180 and the lightemitting structure 120 can be electrically connected to each other.

Since the insulation supports 170 included in the light emitting deviceaccording to the present disclosure include the coupling pattern beforethe bulk electrodes 180 are formed, the bulk electrodes 180 formed inthe internal opening regions by the method such as the plating method,or the like, can have the coupling pattern naturally engaged with thecoupling pattern of the insulation supports 170.

The bulk electrode 180 can sequentially include a conduction layer, abarrier layer, and an oxidation preventing layer. The conduction layer,which is a layer for diffusing a current, can include Cu, or Ag, or thelike. The barrier layer, which is a layer for preventing diffusion ofmetal atoms included in the bulk electrode 180, can include Ni, or Pd,or the like. The oxidation preventing layer, which is a layer forpreventing oxidation of the bulk electrode 180, can be formed of orinclude Au, or the like, and be replaced by an oxidation sacrificiallayer including Ag and/or Al. The oxidation preventing layer or theoxidation sacrificial layer can be disposed on an upper surface on whichthe bulk electrode 180 is exposed to the outside.

The entire area of a lower surface of the bulk electrode 180 can be 70%,80, or 90% or more of an area of an upper surface of the secondconductive type semiconductor layer. In the present exemplaryembodiment, since the bulk electrodes 180 are formed to have a widearea, heat radiation efficiency of the light emitting device is high.

FIG. 10 is a plan view of a partial region of a wafer before the lightemitting device according to the exemplary embodiment of the presentdisclosure is divided into individual diodes.

Referring to FIG. 10, the support parts 185 can be disposed tocorrespond to the division scheduled lines as illustrated in FIG. 7. Thebulk electrodes 180 can be formed in consideration of positions andareas of the pad metal layers 160 disposed therebelow. The bulkelectrodes 180 and the support parts 185 can be formed through the sameprocess. In some implementations, the insulation supports 170 are formedon the pad metal layers 160, and partial regions of the insulationsupports 170 are patterned to expose portions of the pad metal layers160 and the first insulating layer 150. The patterned regions can be thedivision scheduled regions corresponding to the division scheduledlines. The region opened through the patterning process is applied witha material for forming the above-mentioned bulk electrodes 180 or isburied by a plating process, and the material is hardened, therebymaking it possible to form the bulk electrodes 180 and the support parts185. Therefore, the bulk electrodes 180 and the support parts 185 can beformed in the same process using the same material.

FIG. 11 is a plan view illustrated so that the first conductive typesemiconductor layer 121 is directed upwardly after the growth substrate110 is removed. Therefore, in the present exemplary embodiment, theinsulation supports 170 and the bulk electrodes 180 are positioned belowthe light emitting structure 120.

FIG. 12(a) is a cross-sectional view of an epitaxial layer having aroughness formed on a surface thereof in a state in which the growthsubstrate is separated. FIGS. 12(b) and 12(c) are cross-sectional viewsof the light emitting structure on which a second insulating layer isformed.

FIG. 12(a) is a cross-sectional view taken along line A-A illustrated inFIG. 11, and FIG. 12(b) is a cross-sectional view taken along line A-Aafter the second insulating layer is disposed on an exemplary embodimentillustrated in FIG. 11. FIG. 12(c) is a cross-sectional view taken alongline B-B after the second insulating layer is disposed on the exemplaryembodiment illustrated in FIG. 11.

Next, referring to FIG. 12(a), the growth substrate 110 is separatedfrom the light emitting structure 120. The growth substrate 110 can beseparated from the light emitting structure 120 by a method such as alaser lift-off method, a chemical lift-off method, a stress lift-offmethod, or a thermal lift-off method, or the like. Since the growthsubstrate 110 is removed, heat radiation efficiency and light efficiencyof the light emitting device according to the present disclosure can beimproved.

Exposed surfaces of the bulk electrodes 180 can be planarized throughchemical mechanical polishing. The roughness can be formed on a surfaceof the first conductive type semiconductor layer 121 exposed due to theseparation of the growth substrate 110. In addition, before theroughness is formed, residuals on the surface of the first conductivetype semiconductor layer 121 can be chemically or physically removed,and the first conductive type semiconductor layer 121 can be removed ata predetermined thickness from the surface thereof. In a process ofseparating the growth substrate 110, a defect or damage can be generatedin the vicinity of the first conductive type semiconductor layer 121.Therefore, the surface of the first conductive type semiconductor layer121 is removed at a predetermined thickness, thereby making it possibleto make an average crystalline of the entirety of the first conductivetype semiconductor layer 121 excellent.

The roughness can be formed by wet etching using KOH and/or NaOHsolutions, or a sulfur phosphoric acid, be formed by photo-enhancedchemical (PEC) etching, or be formed by other wet etching, dry etching,or electrolysis. The roughness is formed on the surface of the firstconductive type semiconductor layer 121, such that light extractingefficiency can be improved.

According to various embodiments of the present disclosure, since thebase including the insulation supports 170 and the bulk electrodes 180mechanically coupled to each other serves as a support substrate, eventhough the growth substrate 110 is separated, structural stability ofthe light emitting device can be secured.

Then, referring to FIGS. 12(b) and 12(c), the light emitting structures120 can be patterned to form the light emitting structure 120 and thedivision scheduled regions 300. The patterning can be performed usingdry etching, or the like. The division scheduled region 300 are formed,such that the light emitting structure 120 can be divided into one ormore light emitting devices.

Then, a second insulating layer 190 can be formed on the light emittingstructure 120 and the exposed support parts 185. The second insulatinglayer 190 is not limited as long as it is a transparent insulatinglayer, and can be formed through a depositing process, or the like. Thesecond insulating layer 190 can protect the light emitting structure 120from an external environment.

Then, a process of dividing the wafer into individual devices inconsideration of the division scheduled regions 300 formed by thepatterning is performed. This process can include a cutting processusing a dicing blade such as a diamond blade. The support parts 185disposed in the division scheduled regions 300 can be removed by thecutting process.

In some implementations, the support parts 185 are not completelyremoved and at least a portion of the support parts 185 can remain. Inthis case, a portion of the insulation support 170 can be disposedbetween the support part 185 and the pad metal layer 160, thereby makingit possible to prevent generation of an electric short circuit due to acontact between the support part 185 and the pad metal layer 160.

As a result, the light emitting device according to the exemplaryembodiment of the present disclosure illustrated in FIGS. 13(a) and13(b) is formed. A cross-sectional view of FIG. 13(a) is across-sectional view of the light emitting device viewed in the samedirection as that of the cross-sectional view of FIG. 12(b), and across-sectional view of FIG. 13(b) is a cross-sectional view of thelight emitting device viewed in the same direction as that of thecross-sectional view of FIG. 12(c).

FIG. 14(a) is a cross-sectional view for describing an exemplary lightemitting device according to some embodiments of the present disclosure.

Referring to FIG. 14(a), a light emitting device 400 is the lightemitting device according to the exemplary embodiment of the presentdisclosure described above, and is mounted on a sub-mount substrate 500.

The sub-mount substrate 500 includes a substrate 530 and electrodepatterns 520 disposed on the substrate 530. The substrate 530 can be anyone of BeO, SiC, Si, Ge, SiGe, or AIN, or ceramic substrates havingexcellent thermal conductivity. However, the substrate 530 is notlimited thereto, and other implementations are also possible, but can bea substrate including a metal material having high thermal conductivityand excellent electrical conductivity as well as an insulating materialhaving high thermal conductivity.

When the electrode patterns 520 are formed to have a shape correspondingto that of the bulk electrodes 180, the bulk electrodes 180 are bondedto the electrode patterns 520, respectively. Here, the bulk electrodes180 can be bonded to the electrode patterns 520 using heat or anultrasonic wave or both of the heat and the ultrasonic wave.Alternatively, the bulk electrodes 180 can be bonded to the electrodepatterns 520 using a solder paste.

The bulk electrodes 180 and the electrode patterns 520 can be bonded toeach other by various bonding methods as described above through bondingregions 510.

FIG. 14(b) is a perspective view for describing an exemplary lightemitting device package according to some embodiments of the presentdisclosure.

Referring to FIG. 14(b), the light emitting device package includes asubstrate 300 including a first frame 311, a second frame 313, and aninsulating layer 315 disposed between the first and second frames 311and 313, and a light emitting device 400, a sub-mount substrate 500, andwires 330 mounted in a cavity 317 formed in an upper surface of thesubstrate 300.

The light emitting device 400 can include the light emitting deviceaccording to the exemplary embodiments described above.

The first and second frames 311 and 313 can be or include metal framesor ceramic frames. In the case in which the first and second frames 311and 313 are the metal frames, they can include a single metal includingAl, Ag, Cu, or Ni, or the like, having excellent electricalcharacteristics and heat radiation characteristics, or an alloy thereof.

The insulating layer 315 can include an adhering part, and serves to fixthe first and second frames 311 and 313 to both sides thereof. Power canbe supplied to the light emitting device 400 by connecting pads and apower supply to each other through the wires 330.

FIGS. 15(a) to 15(f) are cross-sectional views and a plan view fordescribing exemplary light emitting devices and exemplary methods ofmanufacturing the same according to some embodiments. Exemplaryembodiments of FIGS. 15(a) to 15(f) are the same as that of FIG. 13(b)except for forms of bulk electrodes 180 and insulation supports 170.Therefore, an overlapped description will be omitted.

Referring to FIGS. 15(a) to 15(f), the bulk electrodes 180 and/or theinsulation supports 170 can have a multi-stage structure. For example,upper and lower portions of the bulk electrodes 180 and/or theinsulation supports 170 can have different widths. In addition, the bulkelectrodes 180 and/or the insulation supports 170 can be formed in aprocess before the wafer according to the present exemplary embodimentsis divided into individual diodes.

Again referring to FIG. 15(a), the insulation supports 170 can coverportions of lower surfaces of the bulk electrodes 180. That is, theinsulation supports 170 can cover the bulk electrodes 180 except forlower opening regions of the bulk electrodes 180. In the presentdisclosure, the bulk electrodes 180 can be disposed more adjacently toeach other as compared with the related art. Therefore, at the time ofmounting the light emitting device on a printed circuit board, or thelike, through a solder paste, or the like, a short circuit between thebulk electrodes 180 due to the solder paste can be problematic. However,in the present exemplary embodiment, portions of the lower surfaces ofthe bulk electrodes 180 except for the lower opening regions of thelower surfaces of the bulk electrodes 180 are covered with theinsulation supports 170, thereby making it possible to prevent the shortcircuit between the bulk electrodes 180 due to the solder paste. Thatis, concave parts exposing the lower surfaces of the bulk electrodes 180are formed, and side walls of the concave parts are formed of theinsulation supports 170, thereby making it possible to prevent the shortcircuit between the bulk electrodes 180.

According to an exemplary embodiment of FIG. 15(a), the insulationsupports 170 covering outer side regions of the bulk electrodes 180 canbe formed by an additional process after the bulk electrodes 180 aredisposed in internal regions of the insulation supports 170 by a platingtechnology, or the like.

Again referring to FIG. 15(b), an exemplary embodiment of FIG. 15(b) isdifferent from that of FIG. 15(a) in that an insulation support 170disposed between the bulk electrodes 180 is formed in a multi-stagestructure in the bulk electrodes 180. In the present exemplaryembodiment, both of the bulk electrodes 180 and the insulation support170 have a multi-stage structure in which upper and lower ends thereofhave different widths. According to the exemplary embodiment of FIG.15(b), the bulk electrodes 180 are formed until before a width of theinsulation support 170 disposed between the bulk electrodes 180 ischanged. Then, partial regions of the bulk electrodes 180 are coveredwith the insulation support 170 disposed between the bulk electrodes180. Again, the bulk electrodes 180 are formed, and outer side regionsof the bulk electrodes 180 of which formation is completed are coveredwith the insulation supports 170, thereby making it possible to form ashape of the insulation supports 170.

Again referring to FIG. 15(c), an exemplary embodiment of FIG. 15(c) isthe same as that of FIG. 15(b) except that lower surfaces of the bulkelectrodes 180 and lower surfaces of the insulation supports 170 areflat in parallel with each other. In the present exemplary embodiment,an insulation support 170 disposed in facing regions of the bulkelectrodes 180 has a multi-stage structure, and bulk electrodes 180facing each other also have a multi-stage structure.

Therefore, the short circuit between the bulk electrodes 180 due to thesolder paste can be prevented without disposing the insulation supports170 covering outer side regions of the lower surfaces of the bulkelectrodes 180.

Again referring to FIG. 15(d), an exemplary embodiment of FIG. 15(d) isthe same as that of FIG. 15(c) except that a width of the insulationsupport 170 in the bulk electrodes 180 has a gradient that iscontinuously increased from an upper end of the insulation support 170toward a lower end thereof. In addition, widths of the bulk electrodes180 can have a gradient that is continuously increased from lower endsof the bulk electrodes 180 toward upper ends thereof.

In the present exemplary embodiment, the width of the insulation support170 disposed between the bulk electrodes 180 can be continuouslyincreased. In order to form a shape of the insulation supports 170according to the present exemplary embodiment, in the light emittingdevice according to the exemplary embodiment of the present disclosuredescribed above, an etching process, or the like, is performed so that agroove having a gradient is formed in a region between the bulkelectrodes 180 after the formation of the insulation supports 170 andthe bulk electrodes 180 of which the lower surfaces are flat iscompleted. Then, the groove is filled with the insulation support 170,thereby making it possible to form the shape of the insulation supports170 according to the exemplary embodiment of FIG. 15(d). Alternatively,after the bulk electrodes 180 are formed through plating, or the like,so that a groove having a gradient is formed between the bulk electrodes180 at the time of forming the bulk electrodes 180, the groove is filledwith the insulation support 170, thereby making it possible to form theshape of the insulation support 170 according to the present exemplaryembodiment.

Again referring to FIG. 15(e), an exemplary embodiment of FIG. 15(e) isthe same as that of FIG. 15(d) except that the insulation supports 170cover outer side regions of the lower surfaces of the bulk electrodes180. A shape of the insulation supports 170 according to the presentexemplary embodiment can be formed through an additional process ofcovering the outer side regions of the lower surfaces of the bulkelectrodes 180 after the shape of the insulation supports 170 accordingto the exemplary embodiment of FIG. 15(d) is formed.

In the present disclosure, the exemplary embodiments of FIGS. 15(a),15(b) and 15(e) have a common point in that the lower surfaces of thebulk electrodes 180 and the insulation supports 170 are not in parallelwith each other, the concave parts exposing the lower surfaces of thebulk electrodes 180 are formed, and the sidewalls of the concave partsare formed of the insulation supports 170. In the present exemplaryembodiments, since the solder paste can be accommodated through theconcave parts to fix the light emitting device, alignment can be easilymade in a surface mounting process.

FIG. 15(f) is a plan view in which the bulk electrodes 180 are disposedto be viewed in the exemplary embodiments of FIGS. 15(a), 15(b), and15(e). A coupling pattern below the insulation support 170 is denoted bya dotted line.

Referring to FIG. 15(f), a portion of each of the bulk electrodes 180 isexposed through the concave part of the lower surface of the insulationsupport 170. Each of the exposed bulk electrodes 180 can be electricallyconnected to electrode patterns having a positive electrode and anegative electrode.

In the present disclosure, although not illustrated, before or after thewafer is divided into unit diodes, a wavelength converting layer can bedeposited or coated on the light emitting device, which is the wafer orthe unit diode on which the second insulating layer 190 is formed. Thewavelength converting layer can have a uniform thickness. The wavelengthconverting layer can contain a phosphor converting a wavelength of thelight generated in the active layer 123 and a resin. The phosphor can bemixed with the resin and be randomly or uniformly disposed.

The resin can include a polymer resin such as an epoxy resin or an acrylresin, or a silicon resin, and serve as a matrix dispersing thephosphor. The phosphor can include various phosphors known in the art,and can include at least one of, for example, a garnet phosphor, analuminate phosphor, a sulfide phosphor, an oxynitride phosphor, anitride phosphor, a fluoride-based phosphor, or a silicate phosphor.However, the present disclosure is not limited thereto, and otherimplementations are also possible.

The wavelength converting layer can be deposited or coated using variousmethods such as aerosol, pulsed laser deposition (PLD), printing, orspin coating using spin-on-glass (SOG), and the like.

In addition, in the present disclosure, although not illustrated, anoptical glass lens can be disposed on the light emitting device, whichis a wafer or a unit device on which the second insulating layer 190 isformed, before or after the waver is divided into individual devices.The optical glass lens can control a beam angle of the light generatedin the active layer 123. In addition, a secondary optical lens can beformed on the light emitting device using an optical glass lens having amicro lens or Fresnel lens form. The optical glass lens can adhere tothe light emitting device using SOG or a transparent organic material asan adhesive. The optically transparent SOG or the transparent organicmaterial is used, thereby making it possible to decrease light loss.Further, the optical glass lens can be formed after the above-mentionedwavelength converting layer is formed on the light emitting device.

In the present disclosure, the light emitting device can be directlymounted on the printed circuit board through the bulk electrodes 180enclosed or surrounded by the insulation supports 170, and the sidesurfaces of the bulk electrodes 180 are not exposed, such that diffusionof a metal element such as tin (Sn), or the like, in the solder paste tothe light emitting device can be prevented. In addition, since theinsulation supports 170 and the bulk electrodes 180 included in thelight emitting device according to the present disclosure can bemechanically coupled to each other in the coupling regions 175,reliability of the light emitting device can be improved. In addition,since the bulk electrodes 180 can be disposed adjacently to each other,heat radiation efficiency of the light emitting device can be improved.

FIGS. 16 and 17 respectively show a plan view and a cross-sectional viewof an exemplary light emitting device according to some embodiments ofthe present disclosure. FIG. 17 illustrates a cross section taken byline I-I′ of FIG. 16 FIGS. 18(a) to 18(d) are plan views of lightemitting devices according to some embodiments of the presentdisclosure.

Referring to FIGS. 16 and 17, the light emitting device includes a lightemitting structure 220, a first contact electrode 230, a second contactelectrode 240, insulating layers 250 and 260, first and second bulkelectrodes 271 and 273, and an insulation support 280. Further, thelight emitting device can further include a growth substrate (notillustrated), a connecting electrode 245, and a stress buffering layer265.

The light emitting structure 220 includes a first conductive typesemiconductor layer 221, an active layer 223 disposed on the firstconductive type semiconductor layer 221, and a second conductive typesemiconductor layer 225 disposed on the active layer 223. The firstconductive type semiconductor layer 221, the active layer 223, and thesecond conductive type semiconductor layer 225 can include a III-V basedcompound semiconductor, for example, a nitride based semiconductor suchas (Al, Ga, In)N. The first conductive type semiconductor layer 221 caninclude n-type impurities (for example, Si), and the second conductivetype semiconductor layer 225 can include p-type impurities (for example,Mg), and vice versa. The active layer 223 can include a multi-quantumwell (MQW) structure, and a composition ratio of the active layer 223can be determined so that light having a desired peak wavelength isemitted.

In addition, the light emitting structure 220 can include a region inwhich the first conductive type semiconductor layer 221 is partiallyexposed by partially removing the second conductive type semiconductorlayer 225 and the active layer 223. For example, as illustrated in FIG.17, the light emitting structure 220 can include at least one hole 220 apenetrating through the second conductive type semiconductor layer 225and the active layer 223 to expose the first conductive typesemiconductor layer 221. The number of holes 220 a can also be plural,and a form and a layout of the hole 220 a are not limited to thoseillustrated in FIG. 17. In addition, the region in which the firstconductive type semiconductor layer 221 is partially exposed can also beprovided by partially removing the second conductive type semiconductorlayer 225 and the active layer 223 to form a mesa including the secondconductive type semiconductor layer 225 and the active layer 223.

In some implementations, the light emitting structure 220 can furtherinclude a rough surface 220R formed by increasing a roughness of a lowersurface thereof. The rough surface 220R can be formed by at least one ofa wet etching method, a dry etching method, or an electrochemicaletching method, and can be formed using, for example, aphoto-electrochemical (PEC) etching method, an etching method using anetching solution including KOH and NaOH, or the like. Therefore, thelight emitting structure 220 can include protrusion parts and/or concaveparts formed on a surface of the first conductive type semiconductorlayer 221 and having a scale of μm to nm. Light extracting efficiency oflight emitted by the light emitting structure 220 can be improved by therough surface 220R.

In some implementations, the light emitting structure 220 can furtherinclude the growth substrate (not illustrated) positioned below thefirst conductive type semiconductor layer 221. The growth substrate isnot limited as long as the light emitting structure 220 can be grown onthe growth substrate. For example, the growth substrate can be orinclude a sapphire substrate, a silicon carbide substrate, a siliconsubstrate, a gallium nitride substrate, or an aluminum nitridesubstrate, or the like. The growth substrate can be separated andremoved from the light emitting structure 220 using varioustechnologies.

The second contact electrode 240 can be disposed on the secondconductive type semiconductor layer 225, and can form ohmic-contact thesecond conductive type semiconductor layer 225. In some implementations,the second contact electrode 240 can at least partially cover an uppersurface of the second conductive type semiconductor layer 225, and canbe disposed to generally cover the upper surface of the secondconductive type semiconductor layer 225. Further, the second contactelectrode 240 can be formed to cover the upper surface of the secondconductive type semiconductor layer 225 as a single body in remainingregions except for a position in which the first conductive typesemiconductor layer 221 of the light emitting structure 220 is exposed.Therefore, a current is uniformly supplied to the entire light emittingstructure 220, such that current dispersion efficiency can be improved.However, the present disclosure is not limited thereto, and otherimplementations are also possible. For example, the second contactelectrode 240 can also include a plurality of unit electrodes.

The second contact electrode 240 can be formed of or include a materialthat can form ohmic-contact with the second conductive typesemiconductor layer 225, and can include, for example, a metal materialand/or a conductive oxide.

When the second contact electrode 240 includes the metal material, thesecond contact electrode 240 can include a reflecting layer and a coverlayer covering the reflecting layer. As described above, the secondcontact electrode 240 can serve to reflect the light while formingohmic-contact with the second conductive type semiconductor layer 225.Therefore, the reflecting layer can include a metal that has highreflectivity and can form an ohmic-contact with the second conductivetype semiconductor layer 225. For example, the reflecting layer caninclude Ni, Pt, Pd, Rh, W, Ti, Al, Mg, Ag, or Au or combination ofthereof. In addition, the reflecting layer can include a single layer ormultiple layers.

The cover layer can prevent mutual diffusion between the reflectinglayer and other materials, and prevent damage to the reflecting layerdue to diffusion of external other materials to the reflecting layer.Therefore, the cover layer can be formed to cover a lower surface andside surfaces of the reflecting layer. The cover layer can beelectrically connected together with the reflecting layer to the secondconductive type semiconductor layer 225 to serve as an electrodetogether with the reflecting layer. The cover layer can include, forexample, Au, Ni, Ti, Cr, or the like, and include a single layer ormultiple layers.

The reflecting layer and the cover layer can be formed using e-beamevaporation, or a plating scheme, or the like.

Meanwhile, in the case in which the second contact electrode 240includes the conductive oxide, the conductive oxide can be or includeITO, ZnO, AZO, or IZO, or the like. When the second contact electrode240 includes the conductive oxide, it is possible to increase region ofthe upper surface of the second conductive type semiconductor layer 225covered by the second contact electrode 240 as compared to when thesecond contact electrode 240 includes the metal. A spaced distance froman edge of the region in which the first conductive type semiconductorlayer 221 is exposed to the second contact electrode 240 can berelatively shorter when the second contact electrode 240 is made of orincludes the conductive oxide. In this case, since the shortest distancefrom a portion at which the second contact electrode 240 and the secondconductive type semiconductor layer 225 contact each other to a portionat which the first contact electrode 230 and the first conductive typesemiconductor layer 221 contact each other can become relativelyshorter, a forward voltage Vf of the light emitting device can bedecreased.

This is due to a difference between manufacturing methods in the case inwhich the second contact electrode 240 is made of or includes the metalmaterial and in the case in which the second contact electrode 240 ismade of or includes the conductive oxide. For example, since the metalmaterial is formed in a depositing or plating scheme, it is formed at aportion spaced apart from an outer edge of the second conductive typesemiconductor layer 225 by a predetermined distance by a process marginof a mask. On the other hand, the conductive oxide is generally formedon the second conductive type semiconductor layer 225 and is thenremoved by the same process in an etching process of exposing the firstconductive type semiconductor layer 221. Therefore, the conductive oxidecan be formed to be relatively closer to the outer edge of the secondconductive type semiconductor layer 225. However, the present disclosureis not limited thereto, and other implementations are also possible.

In addition, in the case in which the second contact electrode 240includes ITO, a first insulating layer 250 includes SiO₂, and the firstcontact electrode 230 includes Ag, an omni-reflector including a stackstructure of ITO/SiO₂/Ag can be formed.

The insulating layers 250 and 260 partially cover the first and secondcontact electrodes 230 and 240, and insulate the first and secondcontact electrodes 230 and 240 from each other. The insulating layers250 and 260 can include the first insulating layer 250 and a secondinsulating layer 260. Next, the first insulating layer 250 will be firstdescribed, and a content associated with the second insulating layer 260will be subsequently described.

The first insulating layer 250 can partially cover an upper surface ofthe light emitting structure 220 and the second contact electrode 240.In addition, the first insulating layer 250 can cover side surfaces ofthe hole 220 a and partially expose the first conductive typesemiconductor layer 221 exposed in the hole 220 a. The first insulatinglayer 250 can include an opening part disposed at a portioncorresponding to the hole 220 a and an opening part exposing a portionof the second contact electrode 240. The first conductive typesemiconductor layer 221 and the second contact electrode 240 can bepartially exposed through the above-mentioned opening parts.

The first insulating layer 250 can include an insulating material, forexample, SiO₂, SiN_(x), or MgF₂, or the like. Further, the firstinsulating layer 250 can include multiple layers, and include adistributed Bragg reflector in which materials having differentrefractive indices are alternately stacked.

In the case in which the second contact electrode 240 includes aconductive oxide, the first insulating layer 250 includes thedistributed Bragg reflector, thereby making it possible to improve lightemitting efficiency of the light emitting device. In addition, unlikethis, the second contact electrode 240 includes a conductive oxide, andthe first insulating layer 250 is made of or includes a transparentinsulating oxide (for example, SiO₂), thereby making it possible to forman omni-reflector by a stack structure of the second contact electrode240, the first insulating layer 250, and the first contact electrode230. In some implementations, the first contact electrode 230 is formedto substantially generally cover a surface of the first insulating layer250 except for a region in which a portion of the second contactelectrode 240 is exposed.

Therefore, a portion of the first insulating layer 250 can be interposedbetween the first and second contact electrodes 230 and 240.

In some implementations, the first insulating layer 250 can furthercover at least a portion of a side surface of the light emittingstructure 220. A degree in which the first insulating layer 250 coversthe side surface of the light emitting structure 220 can be changeddepending on isolation in a chip unit in a process of manufacturing thelight emitting device. In some implementations, the first insulatinglayer 250 can be formed to cover only the upper surface of the lightemitting structure 220. Alternatively, in the case in which the firstinsulating layer 250 is formed after the wafer is isolated in a chipunit in the process of manufacturing the light emitting device, the sidesurface of the light emitting structure 220 can also be covered by thefirst insulating layer 250.

The first contact electrode 230 can partially cover the light emittingstructure 220. In addition, the first contact electrode 230ohmic-contacts the first conductive type semiconductor layer 221 throughthe hole 220 a and the opening part of the first insulating layer 250disposed at the portion corresponding to the hole 220 a. In the presentexemplary embodiment, the first contact electrode 230 can be formed togenerally cover other portions except for a partial region of the firstinsulating layer 250. Therefore, the light can be reflected through thefirst contact electrode 230. In addition, the first contact electrode230 can be electrically insulated from the second contact electrode 240by the first insulating layer 250.

The first contact electrode 230 is formed to generally cover the uppersurface of the light emitting structure 220 except for a partial region,thereby making it possible to further improve the current dispersionefficiency. In addition, since the first contact electrode 230 can covera portion that is not covered by the second contact electrode 240, itmore effectively reflects the light, thereby making it possible toimprove the light emitting efficiency of the light emitting device.

As described above, the first contact electrode 230 can serve to reflectthe light simultaneously with ohmic-contacting the first conductive typesemiconductor layer 221. Therefore, the first contact electrode 230 caninclude a high reflective metal layer such as an Al layer. Here, thefirst contact electrode 230 can be formed of or include a single layeror multiple layers. The high reflective metal layer can be formed on anadhesion layer made of or including Ti, Cr, Ni, or the like. However,the present disclosure is not limited thereto, and other implementationsare also possible. That is, the first contact electrode 230 can alsoinclude at least one of Ni, Pt, Pd, Rh, W, Ti, Al, Mg, Ag, or Au.

In some implementations, the first contact electrode 230 can also beformed to cover side surfaces of the light emitting structure 220. Inthe case in which the first contact electrode 230 is also formed on theside surface of the light emitting structure 220, it reflects lightemitted from the active layer 223 to the side surface upwardly toincrease a ratio of the light emitted to an upper surface of the lightemitting device. In the case in which the first contact electrode 230 isformed to cover the side surface of the light emitting structure 220,the first insulating layer 250 can be interposed between the sidesurface of the light emitting structure 220 and the first contactelectrode 230.

Meanwhile, the light emitting device can further include a connectingelectrode 245. The connecting electrode 245 can be disposed on thesecond contact electrode 240, and can be electrically connected to thesecond contact electrode 240 through the opening part of the firstinsulating layer 250. Further, the connecting electrode 245 canelectrically connect the second contact electrode 240 and the secondbulk electrode 273 to each other. In addition, the connecting electrode245 can be formed to partially cover the first insulating layer 250, andcan be spaced apart and be insulated from the first contact electrode230.

An upper surface of the connecting electrode 245 can be formed at aheight that is substantially the same as that of an upper surface of thefirst contact electrode 230. In addition, the connecting electrode 245can be formed by the same process as that of the first contact electrode230, and the connecting electrode 245 and the first contact electrode230 can include the same material. However, the present disclosure isnot limited thereto, and other implementations are also possible. Forexample, the connecting electrode 245 and the first contact electrode230 can include different materials.

The second insulating layer 260 can partially cover the first contactelectrode 230, and can include a first opening part 260 a partiallyexposing the first contact electrode 230 and a second opening part 260 bpartially exposing the second contact electrode 240. The number of eachof the first and second opening parts 260 a and 260 b can be one ormore.

The second insulating layer 260 can include an insulating material, forexample, SiO₂, SiN_(x), or MgF₂, or the like. Further, the secondinsulating layer 260 can include multiple layers, and include adistributed Bragg reflector in which materials having differentrefractive indices are alternately stacked. In the case in which thesecond insulating layer 260 is formed of or includes the multiplelayers, the uppermost layer of the second insulating layer 260 can beformed of or include SiN_(x). The uppermost layer of the secondinsulating layer 260 is made of SiN_(x), thereby making it possible tomore effectively prevent moisture from permeating into the lightemitting structure 220.

The stress buffering layer 265 is disposed on the insulating layers 250and 260. In some implementations, the stress buffering layer 265 can bedisposed on the second insulating layer 260. The stress buffering layer265 can at least partially cover an upper surface of the secondinsulating layer 260, as illustrated. In some implementations, thestress buffering layer 265 can further cover portions of side surfacesof the second insulating layer 260. In this case, the stress bufferinglayer 265 can contact the first contact electrode 230 and the connectingelectrode 245. For example, the stress buffering layer 265 can furthercover side surfaces of the first and second opening parts 260 a and 260b.

The stress buffering layer 265 serves to relax stress generated at thetime of driving the light emitting device. The stress buffering layer265 can have a relatively large Young's modulus. Therefore, the stressbuffering layer shows low strain behavior even at high stress.Therefore, an effect that energy is absorbed by the stress bufferinglayer 265 is generated, thereby making it possible to decrease stressapplied to the light emitting structure 220, the first and secondcontact electrodes 230 and 240, the insulating layers 250 and 260, thefirst and second bulk electrodes 271 and 273, and the insulation support280. The stress applied to the above-mentioned other components isrelaxed by the stress buffering layer 265, such that mechanicalstability of the light emitting device is improved and the possibilitythat a crack and a failure will be generated is decreased, therebyimproving reliability of the light emitting device.

In addition, the stress buffering layer 265 can have residual stress(generated by predetermined stress) lower than that of the insulatinglayers 250 and 260 and/or the insulation support 280. Therefore, thestress buffering layer 265 can relax the stress applied to theabove-mentioned other components by the residual stress in a process ofrepeatedly turning on or off the light emitting device. In addition, thestress buffering layer 265 can have a relatively excellent moistureabsorbing feature. For example, a moisture absorbing feature of thestress buffering layer 265 can be lower than that of the insulationsupport 280. The stress buffering layer 265 has a relatively lowmoisture absorbing feature, thereby making it possible to prevent crackand delamination phenomenon generated by moisture permeating into thelight emitting device.

Furthermore, adhesion between the stress buffering layer 265 and theinsulation support 280 can be higher than that between the insulatinglayers 250 and 260 and the insulation support 280. Therefore, thepossibility that separation or delamination will be generated on aninterface can be significantly decreased in the case in which theinsulation support 280 is formed on the stress buffering layer 265 ascompared with in the case in which the insulation support 280 is formedon the second insulating layer 260.

The stress buffering layer 265 having the above-mentioned effect caninclude an insulating material showing stress relaxing behavior andhaving a moisture permeation preventing effect and adhesion improvingeffect. For example, the stress buffering layer can include at least oneof polyimide, Teflon, benzocyclobutene (BCB), or parylene. In someimplementations, the stress buffering layer 265 can include aphotosensitive material (for example, polyimide), and in the case inwhich the stress buffering layer 265 includes the photosensitivematerial, the stress buffering layer 265 can be formed by only a processof developing the photosensitive material. Therefore, a separateadditional patterning process can be omitted, such that a process ofmanufacturing the light emitting device can be simplified. The stressbuffering layer 265 can contact the first bulk electrode 271, the secondbulk electrode 273, and the insulation support 280.

A thickness of the stress buffering layer 265 is not limited as long asthe stress buffering layer 265 can obtain effective stress relaxingbehavior and permeation preventing effects, and can be about 2 to 30 μm.However, the present disclosure is not limited thereto, and otherimplementations are also possible.

The stress buffering layer 265 can be formed through depositing andpatterning processes. Further, the stress buffering layer 265 and thesecond insulating layer 260 can be simultaneously patterned. Forexample, the second insulating layer 260 covering the first contactelectrode 230 is formed, the stress buffering layer 265 is formed on thesecond insulating layer 260, and the second insulating layer 260 and thestress buffering layer 265 are simultaneously patterned, thereby makingit possible to provide the stress buffering layer 265 as illustrated.However, the present disclosure is not limited thereto, and otherimplementations are also possible.

Meanwhile, the stress buffering layer 265 can also be omitted.

The first bulk electrode 271 and the second bulk electrode 273 can bedisposed on the light emitting structure 220, and be electricallyconnected to the first contact electrode 230 and the second contactelectrode 240, respectively. In some implementations, the first andsecond bulk electrodes 271 and 273 can directly or electricallyconnected to the first and second contact electrodes 230 and 240,respectively. Here, the first and second bulk electrodes 271 and 273 canbe electrically connected to the first and second contact electrodes 230and 240 through the first and second opening parts 260 a and 260 b,respectively.

The first bulk electrode 271 can include a protrusion 271 a protrudingfrom a side surface of the first bulk electrode 271 facing the secondbulk electrode 273. The second bulk electrode 273 includes a concavepart 273 a depressed from a side surface of the second bulk electrode273 facing the first bulk electrode 271. The protrusion part 271 a andthe concave part 273 a are included in the first bulk electrode 271 andthe second bulk electrode 273, respectively, such that a horizontalcross-sectional area of the first bulk electrode 271 can be relativelyincreased and a horizontal cross-sectional area of the second bulkelectrode 273 can be relatively decreased. Therefore, the horizontalcross-sectional area of the first bulk electrode 271 is greater thanthat of the second bulk electrode 273.

In addition, a virtual line D1-D1′ formed along a spaced region wherethe first and second bulk electrodes 271 and 273 face each other canhave one or more bending portion. Although the virtual line D1-D1′having the one or more bending portions. can have corresponding shapesand layouts to those of the protrusion part 271 a and the concave part273 a, the present disclosure is not limited thereto, and otherimplementations are also possible. A starting point and an ending pointof the virtual line D1-D1′ can be disposed on the same line. Asillustrated, the starting point and the ending point of the virtual lineD1-D1′ can be substantially disposed on a line uniformly bisecting thelight emitting device, and the virtual line D1-D1′ is bent such that thevirtual line D1-D1′ can be positioned so that a portion thereof islocated closer to the second bulk electrode 273.

The protrusion part 271 a and the concave part 273 a can be provided ina form in which they are engaged with each other. For example, asillustrated in FIG. 16, a degree in which the concave part 273 a isconcavely depressed and a position of the concave part 273 a cansubstantially correspond to a degree in which the protrusion part 271 aprotrudes and a position of the protrusion part 271 a, respectively.Therefore, a spaced distance between the first and second bulkelectrodes 271 and 273 can be substantially constant.

Meanwhile, shapes of the protrusion part 271 a and the concave part 273a are not limited to shapes illustrated in FIG. 16. For example, asillustrated in FIG. 18(a), a protrusion part 271 a can have a varyingwidth in a protrusion direction from the side surface of the first bulkelectrode to a surface of the protrusion part 271 a. In someimplementations, a width of the protrusion part 271 a can be decreasedin the protrusion direction. The concave part 273 b can also have avarying width in a depression direction from the side surface of thesecond bulk electrode to a surface of the concave part 273 b. In someimplementations, a width of the concave part 273 b can be decreased inthe depression direction, so as to correspond to the protrusion part 271b. Here, a virtual line D2-D2′ extended along a spaced region betweenthe first and second bulk electrodes 271 and 273 that face each othercan have one or more bending portion. In addition, as illustrated inFIG. 18(b), multiple protrusion parts 271 c can be formed, and one ormore concave parts 273 c having a shape corresponding to a protrusionshape of at least some of the plurality of protrusion parts 271 c can beformed. Here, a virtual line D3-D3′ extended along a spaced regionbetween the first and second bulk electrodes 271 and 273 that face eachother can have one or more bending portion, and can have bendingportions more than that of an exemplary embodiment of FIG. 18(a). Inaddition, as illustrated in FIG. 18(c), a protrusion part 271 d can havea varying width in a protrusion direction, for example, a widthincreased in the protrusion direction. The concave part 273 d can alsohave a varying width in a depression direction, for example, a widthdecreased in the depression direction, so as to correspond to theprotrusion part 271 d. Here, a virtual line D4-D4′ extended along aspaced region between the first and second bulk electrodes 271 and 273that face each other can have one or more bending portions. In addition,as illustrated in FIG. 18(d), multiple protrusion parts 271 e can beformed, and one or more concave parts 273 e having a shape correspondingto a protrusion shape of at least some of the plurality of protrusionparts 271 e can be formed. Outer sides of the protrusion part 271 e andthe concave part 273 e can be formed in a curved shape. Here, a virtualline D5-D5′ extended along a spaced region between the first and secondbulk electrodes 271 and 273 that face each other can have one or morebending portions.

However, the present disclosure is not limited thereto, and otherimplementations are also possible. For example, shapes of the protrusionpart 271 a and the concave part 273 a can be variously modified.

Heat is generated at the time of driving the light emitting device.However, since the insulation support 280 and the bulk electrodes 271and 273 have different coefficients of thermal expansion, when the heatis generated, stress is applied to the insulation support 280 and thebulk electrodes 271 and 273. In some implementations, relatively greaterstress is applied to a region between the first and second bulkelectrodes 271 and 273, and thus, a crack can be generated in theinsulation support 280, and a phenomenon that the insulation support 280and the bulk electrodes 271 and 273 are delaminated from each other canbe generated. In the case in which the region between the bulkelectrodes 271 and 273 is formed in a straight line shape, the crackgenerated in the insulation support 280 easily propagates in a straightline direction to cause damage to the light emitting device. Forexample, in a virtual line defined to intersect between the bulkelectrodes 271 and 273 and having a straight line shape, in the case inwhich the virtual line is formed to be overlapped with only theinsulation support 280 without being overlapped with the bulk electrodes271 and 273, the crack generated between the bulk electrodes 271 and 273easily propagates along the virtual line, such that a problem that theinsulation support 280 is separated is generated.

According to the present exemplary embodiment, the first bulk electrode271 includes the protrusion part 271 a, the second bulk electrode 273includes the concave part 273 a, and the virtual line D1-D1′ extendedalong the spaced region between the first and second bulk electrodes 271and 273 that face each other has the at least one bending portion,thereby increasing resistance to stress of the insulation support 280 ofa portion between the bulk electrodes 271 and 273. In addition, eventhough a crack is generated in the insulation support 280 of the portionbetween the bulk electrodes 271 and 273, the at least one bendingportion is formed between the region between the bulk electrodes 271 and273, such that propagation of the crack can be suppressed. In someimplementations, at least portions of the bulk electrodes 271 and 273are overlapped with another virtual line connecting the starting pointand the ending point of the virtual line D1-D1′ to each other and havinga straight line shape, thereby blocking the crack from propagating whiletraversing the insulation support 280 by the portions of the bulkelectrodes 271 and 273 overlapped with another virtual line having thestraight line shape. Therefore, even though the crack is generated inthe insulation support 280, a phenomenon that the insulation support 280is separated can be effectively prevented.

Furthermore, mechanical stability of the insulation support 280 and thebulk electrodes 271 and 273 is increased, and resistance to the stressis improved, thereby making it possible to suppress the crack or thedamage from being generated in the insulation support 280 or suppressthe insulation support 280 and the bulk electrodes 271 and 273 frombeing delaminated from each other in a process of separating the growthsubstrate in a process of manufacturing the light emitting device.

Therefore, the light emitting device according to the present exemplaryembodiment has excellent mechanical stability. For example, the lightemitting device having excellent reliability by preventing the crack andthe damage of the insulation support 280 can be provided. Further, sincethe possibility that a defect of the light emitting device will begenerated in a manufacturing process according to a structure of thelight emitting device according to the present exemplary embodiment isdecreased, a process yield of the light emitting device can be improved.

Furthermore, the first bulk electrode 271 includes the protrusion part271 a, such that the horizontal cross-sectional area of the first bulkelectrode 271 is greater than that of the second bulk electrode 273,thereby improving the heat radiation efficiency of the light emittingdevice. In the case in which the first conductive type semiconductorlayer 221 is an N-type semiconductor layer, the first bulk electrode 271can also serve as an N-type electrode, and light emission and heatgeneration at the time of driving the light emitting device arerelatively concentrated in a region in which the first bulk electrode271 is positioned. Therefore, the horizontal cross-sectional area of thefirst bulk electrode 271 is formed to be greater than that of the secondbulk electrode 273 like the present exemplary embodiment to make thelight emission in the entire light emitting region of the light emittingdevice uniform, thereby making it possible to improve light emittingcharacteristics, and the heat is effectively radiated through the firstbulk electrodes 271, thereby making it possible to improve the heatradiation efficiency of the light emitting device. Therefore, atemperature difference depending on a position of the light emittingstructure 220 is minimized, thereby making it possible to improvetemperature uniformity. An excessive rise in a bonding temperature Tj ata specific portion of the light emitting structure 220 is alsoprevented, such that a decrease in efficiency of the light emittingdevice can be prevented, thereby making it possible to improvereliability of the light emitting device.

Further, the spaced distance between the first and second bulkelectrodes 271 and 273 is substantially constant, such that a phenomenonthat a ratio of an area occupied by surfaces of the first and secondbulk electrodes 271 and 273 to an upper surface of the light emittingdevice is decreased by the protrusion part 271 a and/or the concave part273 a can be minimized. Therefore, even though the protrusion part 271 aand/or the concave part 273 a are formed, a decrease in the heatradiation efficiency due to a decrease in the horizontal cross-sectionalareas of the first and second bulk electrodes 271 and 273 is prevented.

The first and second bulk electrodes 271 and 273 can have a thickness ofseveral tens of micrometers or more, for example, about 70 to 80 μm. Thebulk electrodes 271 and 273 have the thickness in the above-mentionedrange, such that the light emitting device itself can be used in a chipscale package.

The first and second bulk electrodes 271 and 273 can be formed of orinclude a single layer or multiple layers, and can include a materialhaving electrical conductivity. For example, each of the first andsecond bulk electrodes 271 and 273 can include Cu, Pt, Au, Ti, Ni, Al,or Ag, or the like. In some implementations, the first and second bulkelectrodes 271 and 273 can also include metal particles having asintered form and a non-metal material interposed between the metalparticles. The first and second bulk electrodes 271 and 273 can beformed using a plating method, a depositing method, a dotting method, ora screen printing method, or the like. Meanwhile, the first and secondbulk electrodes 271 and 273 can include first and second metal layers271 s and 273 s, respectively. The first and second metal layers 271 sand 273 s can be positioned below the first and second bulk electrodes271 and 273, respectively, to contact the contact electrodes 230 and240, the insulating layers 250 and 260, and the stress buffering layer265. The first and second metal layers 271 s and 273 s can be changeddepending on a method of forming the bulk electrodes 271 and 273, whichwill be described in detail below.

The case in which the first and second bulk electrodes 271 and 273 areformed using the plating method will be first described. A seed metal isformed on an entire surface of the stress buffering layer 265, the firstopening part 260 a, and the second opening part 260 b by a method suchas a sputtering method. The seed metal can include Ti, Cu, Au, or Cr, orthe like, and serve as an under bump metallization (UBM) layer. Forexample, the seed metal can have a stack structure of Ti/Cu. Then, amask is formed on the seed metal. The mask masks a portion correspondingto a region in which the insulation support 280 is formed and opensregions in which the first and second bulk electrodes 271 and 273 areformed. Next, the first and second bulk electrodes 271 and 273 areformed in the open regions of the mask through a plating process. Then,the mask and the seed metal are removed through an etching process, suchthat first and second bulk electrodes 271 and 273 can be provided. Here,the seed metals remaining below the first and second bulk electrodes 271and 273 without being removed become the first and second metal layers271 s and 273 s.

The case in which the first and second bulk electrodes 271 and 273 areformed using the screen printing method will be described. A UBM layeris formed on at least portions of the stress buffering layer 265, thefirst opening part 260 a, and the second opening part 260 b through adepositing and patterning method such as a sputtering method or adepositing and lift-off method. The UBM layer can be formed on regionsin which the first and second bulk electrodes 271 and 273 are to beformed, and can include a (Ti or TiW) layer and a single layer includingCu, Ni, or Au or a combination layer thereof. For example, the UBM layercan have a stack structure of Ti/Cu. The UBM layer corresponds to thefirst and second metal layers 271 s and 273 s. Then, a mask is formed.The mask masks a portion corresponding to a region in which theinsulation support 280 is formed and opens regions in which the firstand second bulk electrodes 271 and 273 are formed. Then, a material suchas an Ag paste, an Au paste, or a Cu paste is formed in the open regionsthrough a screen printing process and is hardened. Next, the mask isremoved through an etching process, such that the first and second bulkelectrodes 271 and 273 can be provided.

The insulation support 280 is disposed on the light emitting structure220, and at least partially covers side surfaces of the bulk electrodes271 and 273. The insulation support 280 has an electrical insulatingproperty, and covers the side surfaces of the first and second bulkelectrodes 271 and 273 to effectively insulate the first and second bulkelectrodes 271 and 273 from each other. At the same time, the insulationsupport 280 can serve to support the first and second bulk electrodes271 and 273. The insulation support 280 can include a material such asan epoxy molding compound or a Si resin. In addition, the insulationsupport 280 can include light-reflective or light scattering particlessuch as TiO₂ particles. For example, in the case in which the insulationsupport 280 includes the EMC, the stress buffering layer 265 can preventthe insulation support 280 from being separated and prevent the moisturefrom permeating into the insulation support 280, as described above.

In some exemplary embodiments, unlike a form illustrated, the insulationsupport 280 can also cover the side surface of the light emittingstructure 220.

In this case, an angle of the light emitted from the light emittingstructure 220 can be changed. For example, in the case in which theinsulation support 280 further covers at least a portion of the sidesurface of the light emitting structure 220, some of the light emittedto the side surface of the light emitting structure 220 can be reflectedtoward the lower surface of the light emitting structure 220. Asdescribed above, a region in which the insulation support 280 isdisposed is adjusted, thereby making it possible to adjust an angle ofthe light emitted by the light emitting device.

FIGS. 19 and 20 are, respectively, a plan view and a cross-sectionalview for describing an exemplary light emitting device according to someembodiments of the present disclosure. FIG. 20 illustrates a crosssection of a portion corresponding to line II-II′ of FIG. 19.

The light emitting device of FIGS. 19 and 20 is different from the lightemitting device of FIGS. 16 and 17 in that an insulation support 280includes an upper insulation support 281 and a lower insulation support283 and the light emitting device further includes pad electrodes 291and 293. Hereinafter, the light emitting device according to the presentexemplary embodiment will be described based on this difference, and adetailed description for overlapped configurations will be omitted.

Referring to FIGS. 19 and 20, the light emitting device includes a lightemitting structure 220, a first contact electrode 230, a second contactelectrode 240, insulating layers 250 and 260, first and second bulkelectrodes 271 and 273, the insulation support 280, and first and secondpad electrodes 291 and 293. Further, the light emitting device canfurther include a growth substrate (not illustrated), a connectingelectrode 245, and a stress buffering layer 265.

The insulation support 280 is disposed on the light emitting structure220, and at least partially covers side surfaces of the bulk electrodes271 and 273 and upper surfaces of the bulk electrodes 271 and 273. Inaddition, the insulation support 280 can include opening parts partiallyexposing the upper surfaces of the first and second bulk electrodes 271and 273. The insulation support 280 can include the upper insulationsupport 281 and the lower insulation support 283. The lower insulationsupport 283 can enclose the side surfaces of the bulk electrodes 271 and273, and the upper insulation support 281 can partially cover the uppersurfaces of the bulk electrodes 271 and 273. In addition, the upperinsulation support 281 can cover an interface between the lowerinsulation support 283 and the bulk electrodes 271 and 273.

The insulation support 280 has an electrical insulating property, andcovers the side surfaces of the first and second bulk electrodes 271 and273 to effectively insulate the first and second bulk electrodes 271 and273 from each other. At the same time, the insulation support 280 canserve to support the first and second bulk electrodes 271 and 273.

The upper surfaces of the bulk electrodes 271 and 273 are partiallycovered by the upper insulation support 281, such that areas of exposedportions in the upper surfaces of the first and second bulk electrodes271 and 273 can be smaller than a horizontal cross-sectional area of thefirst bulk electrode 271 and a horizontal cross-sectional area of thesecond bulk electrode 273, respectively. Particularly, the upperinsulation support 281 can be disposed on the upper surfaces of the bulkelectrodes 271 and 273 in the vicinity of side surfaces of the first andsecond bulk electrodes 271 and 273 facing each other. Therefore, aspaced distance between the upper surface of the first bulk electrode271 and the upper surface of the second bulk electrode 273 exposed bythe opening part of the upper insulation support 281 is greater thanthat between the first and second bulk electrodes 271 and 273.

In more detail, a conductive material (for example, a solder, aconductive adhesive, or an eutectic material, or the like) is formedbetween the exposed upper surfaces 271 a and 273 a and a separatesubstrate to allow the light emitting device and the separate substrateto adhere to each other, thereby making it possible to mount the lightemitting device on the separate substrate. In order to prevent anelectrical short circuit from being generated between the bulkelectrodes 271 and 273 due to the conductive material formed foradhesion, it is required for the spaced distance between the exposedupper surfaces to become a predetermined numerical value or more, asdescribed above. According to the present disclosure, the insulationsupport 280 is formed to partially cover the upper surfaces of the bulkelectrodes 271 and 273, such that the spaced distance between theexposed upper surface of the first bulk electrode 271 and the exposedupper surface of the second bulk electrode 273 can be formed to begreater than that between the first and the second bulk electrodes 271and 273. Therefore, the spaced distance between the exposed uppersurfaces can be formed to be a predetermined numerical value or moreenough to prevent the generation of the electrical short circuit betweenthe bulk electrodes 271 and 273, and the spaced distance between thebulk electrodes 271 and 273 can be formed to be the predeterminednumerical value or less enough to prevent the generation of theelectrical short circuit between the bulk electrodes 271 and 273.Therefore, the heat radiation efficiency of the light emitting devicecan be improved, and the generation of the electrical short circuit in aprocess of mounting the light emitting device can be effectivelyprevented.

The spaced distance between the exposed upper surface of the first bulkelectrode 271 and the exposed upper surface of the second bulk electrode273 is not limited, but can be about 250 μm or more in the case ofmounting the light emitting device on the separate substrate throughsoldering and can be about 80 μm or more in the case of mounting thelight emitting device on the separate substrate through a eutecticbonding process. However, the present disclosure is not limited thereto,and other implementations are also possible.

In addition, it is sufficient that the upper insulation support 281 isdisposed in upper peripheral regions of the side surfaces of the bulkelectrodes 271 and 273 facing each other so that the spaced distancebetween the exposed upper surface of the first bulk electrode 271 andthe exposed upper surface of the second bulk electrode 273 is formed tobe the predetermined numerical value or more, and a form in which theupper insulation support 281 is disposed in other regions is notlimited. For example, as illustrated in FIGS. 19 and 20, the insulationsupport 280 disposed between the first and second bulk electrodes 271and 273 can have a ‘T’ shaped cross section, and the insulation support280 covering outer side surfaces of the first and second bulk electrodes271 and 273 can have a ‘

’ shaped cross section.

In addition, the insulation support 280 and the bulk electrodes 271 and273 can be formed of or include different materials. In someimplementations, the insulation support 280 can include an insulatingpolymer and/or an insulating ceramic, and the bulk electrodes 271 and273 can include a metal material. Therefore, delamination or a crack canbe generated on an interface between the insulation support 280 and thebulk electrodes 271 and 273, and damage due to stress and strain thatcan be caused by bonding different materials to each other can begenerated. When the insulation support 280 and/or the bulk electrodes271 and 273 are damaged, the light emitting structure 220 can bepolluted, and the crack, or the like, can be generated in the lightemitting structure 220, such that reliability of the light emittingdevice can be decreased. According to the exemplary embodiments of thepresent disclosure, the insulation support 280 is formed to partiallycover the side surfaces of the bulk electrodes 271 and 273 and the uppersurfaces of the bulk electrodes 271 and 273, mechanical stabilitybetween the insulation support 280 and the bulk electrodes 271 and 273can be improved. Therefore, reliability of the light emitting device canbe improved.

In addition, mechanical stability of the light emitting device isimproved, thereby making it possible to prevent the light emittingstructure 220 from being damaged in the process of separating the growthsubstrate (not illustrated) from the light emitting structure 220.

Further, the lower insulation support 283 and the upper insulationsupport 281 can be formed of or include the same material or differentmaterials. In the case in which the lower insulation support 283 and theupper insulation support 281 are made of or include the same material,the insulation support 280 can include a material such as an epoxymolding compound (EMC) or a Si resin. In addition, the insulationsupport 280 can include light-reflective and light scattering particlessuch as TiO₂ particles. In the case in which the lower insulationsupport 283 and the upper insulation support 281 are made of or includedifferent materials, the upper insulation support 281 can be formed ofor include a material having brittleness and/or a moisture absorbingfeature lower than those of a material of the lower insulation support283. For example, the lower insulation support 283 can include amaterial such as an epoxy molding compound (EMC) or a Si resin, and theupper insulation support 281 can include a material such as aphoto-resist PR and/or a photo-solder-resist (PSR).

The upper insulation support 281 is made of or includes the materialhaving the relatively lower brittleness, such that the possibility thata failure or a crack will be generated is lower as compared with thelower insulation support 283, thereby making it possible to prevent anexternal pollutant from permeating through an interface between thelower insulation support 283 and the bulk electrodes 271 and 273. Inaddition, the upper insulation support 281 is made of or includes thematerial having the relatively lower moisture absorbing feature, therebymaking it possible to prevent an external pollutant from permeatingthrough the interface between the lower insulation support 283 and thebulk electrodes 271 and 273. For example, in the case in which the lowerinsulation support 283 is made of or includes a material having a highmoisture absorbing feature, such as an EMC, the light emitting devicecan be more effectively protected from moisture by the upper insulationsupport 281 made of or including the material such as the PSR. In someimplementations, in the case in which the upper insulation support 281is formed to cover the interface between the lower insulation support283 and the bulk electrodes 271 and 273, the light emitting deviceprotecting function described above can be more effectively fulfilled.

Meanwhile, an area of the exposed upper surface 271 a of the bulkelectrode 271 can be smaller than that of a region in which the firstbulk electrode 271 and the first contact electrode 230 contact eachother, and an area of the exposed upper surface 273 a of the second bulkelectrode 273 can be greater than that of a region in which the secondbulk electrode 273 and the second contact electrode 240 contact eachother. In this case, the horizontal cross-sectional area of the firstbulk electrode 271 can be greater than that of the second bulk electrode273.

The first and second pad electrodes 291 and 293 can be disposed on thefirst and second bulk electrodes 271 and 273, respectively, and befilled in the opening parts of the insulation support 280 partiallyexposing the upper surfaces of the first and second bulk electrodes 271and 273. Therefore, the first and second pad electrodes 291 and 293 cancover the exposed surfaces of the first and second bulk electrodes 271and 273, respectively. Therefore, a spaced distance between the firstand second pad electrodes 291 and 293 can correspond to those of theexposed upper surfaces of the first and second bulk electrodes 271 and273.

In addition, as illustrated, upper surfaces of the first and second padelectrodes 291 and 293 can be positioned to be substantially flush withthe upper surface of the insulation support 280. In this case, the uppersurface of the light emitting device can be formed to be substantiallyflat. In addition, the upper surfaces of the first and second padelectrodes 291 and 293 can have substantially the same area. Therefore,electrical connection portions exposed on a mounting surface of thelight emitting device can be formed to have the same area, such that amounting process can become easy.

The first and second pad electrodes 291 and 293 can be formed using amethod such as a plating method, or the like, so as to be filled in theopening parts of the insulation support 280. Then, the first and secondpad electrodes 291 and 293 and the insulation support 280 are partiallyremoved using physical and/or chemical methods, for example, a lappingmethod, or a chemical mechanical polishing (CMP) method, or the like,such that the upper surfaces of the first and second pad electrodes 291and 293 can be formed to be flush with the upper surface of theinsulation support 280.

The first and second pad electrodes 291 and 293 can include a conductivematerial, for example, a metal material, for example, Ni, Pt, Pd, Rh, W,Ti, Al, Au, Sn, Cu, Ag, Bi, In, Zn, Sb, Mg, or Pb, or the like. Thefirst and second pad electrodes 291 and 293 can include a material thatis substantially the same as that of the bulk electrodes 271 and 273,and can be formed of or include different materials. The first andsecond pad electrodes 291 and 293 can be formed using a depositingmethod or a plating method, for example, an electroless plating method.

The light emitting device further includes the first and second padelectrodes 291 and 293, such that the upper surface (that can be asurface of the light emitting device mounted on the separate substrate)of the light emitting device can be formed to be substantially flat.Therefore, a process of mounting the light emitting device on theseparate substrate can become easy.

FIGS. 21 and 22 are, respectively, a plan view and a cross-sectionalview for describing an exemplary light emitting device according to someembodiments of the present disclosure. FIG. 22 illustrates a crosssection of a portion corresponding to line III-III′ of FIG. 21.

The light emitting device of FIGS. 21 and 22 is different in structuresof a first contact electrode 230 and an insulating layer 255 from thelight emitting device of FIGS. 16 and 17. Hereinafter, the lightemitting device according to the present exemplary embodiment will bedescribed based on this difference, and a detailed description foroverlapped configurations will be omitted.

Referring to FIGS. 21 and 22, the light emitting device includes a lightemitting structure 220, a first contact electrode 230, a second contactelectrode 240, insulating layers 250 and 260, first and second bulkelectrodes 271 and 273, and an insulation support 280. Further, thelight emitting device can further include a growth substrate (notillustrated), a connecting electrode 245, and a stress buffering layer265.

The light emitting device includes a light emitting structure 220. Thelight emitting structure 220 includes a region in which a firstconductive type semiconductor layer 221 is exposed by partially removinga second conductive type semiconductor layer 225 and an active layer223. The first conductive type semiconductor layer 221 is exposed, suchthat the light emitting structure 220 can have a mesa 220 m includingthe second conductive type semiconductor layer 225 and the active layer223. A position of the mesa 220 m is not limited. For example, asillustrated, the mesa 220 m can be at least partially enclosed by aregion in which the first conductive type semiconductor layer 221 isexposed.

The first contact electrode 230 can be disposed on a region in which thefirst conductive type semiconductor layer 221 is exposed, and canohmic-contact the first conductive type semiconductor layer 221. In someimplementations, unlike the exemplary embodiment of FIGS. 11 and 12, thefirst contact electrode 230 is disposed in a region in which the firstconductive type semiconductor layer 221 is exposed. Therefore, the firstand second contact electrodes 230 and 240 can be spaced apart from eachother.

The insulating layer 225 partially covers the first and second contactelectrodes 230 and 240, and includes first and second opening parts 255a and 255 b partially exposing the first and second contact electrodes230 and 240, respectively. According to the present exemplaryembodiment, since the first contact electrode 230 is disposed in theregion in which the first conductive type semiconductor layer 221 isexposed, the insulating layer 255 cannot be formed in a form in which itis interposed between the first and second contact electrodes 230 and240. In addition, since the insulating layer 255 can be formed byperforming a process once without being separated into the first andsecond insulating layers, a process of manufacturing the light emittingdevice can be further simplified. In some implementations, in the casein which the insulating layer is divided into the first and secondinsulating layers, it is required to perform a mask pattern formingprocess for patterning the respective insulating layers at least twiceor more. On the other hand, in the case of the present exemplaryembodiment, the insulating layer 255 is formed of or includes a singleinsulating layer 255, such that the mask pattern forming process can beomitted at least once or more.

Meanwhile, the connecting electrode 245 can be disposed on the secondcontact electrode 240. In addition, side surfaces of the connectingelectrode 245 can be covered by the insulating layer 255. According tothe present exemplary embodiment, since the insulating layer 255 isformed of or includes the single insulating layer 255, the connectingelectrode 245 can be positioned below the insulating layer 255.

However, in the present exemplary embodiment, the meaning that theinsulating layer 255 is formed of the single insulating layer 255 is notlimited to that the insulating layer 255 is formed of a single layer.Thus, the insulating layer 255 can be formed of or include multiplelayers.

FIGS. 23(a) and 23(b) and FIG. 24 are, respectively, plan views and across-sectional view for describing an exemplary light emitting deviceaccording to some embodiments of the present disclosure.

The light emitting device according to the present exemplary embodimentis different in a structure of the light emitting structure 220 from thelight emitting device of FIGS. 11 and 12, and is also different from thelight emitting device of FIGS. 16 and 17 in that it further includes awavelength converting unit 295 and first and second pad electrodes 291and 293. Therefore, the light emitting device according to the presentexemplary embodiment is different in mutual structure relationshipsbetween other configurations, or the like, from the light emittingdevice of FIGS. 16 and 17. Next, these differences will be mainlydescribed in detail. A detailed description for the same configurationwill be omitted.

FIG. 23(a) is a plan view of the light emitting device according to thepresent exemplary embodiment, FIG. 23(b) is a plan view for describingpositions of holes 220h, and positions of first and second opening parts260 a and 260 b, and FIG. 24 is a cross-sectional view illustrating across section of a region corresponding to line IV-IV′ of FIGS. 23(a)and 23(b).

Referring to FIGS. 23(a), 23(b) and 24, the light emitting deviceincludes a light emitting structure 220, a first contact electrode 230,a second contact electrode 240, insulating layers 250 and 260, a stressbuffering layer 265, first and second bulk electrodes 271 and 273, andan insulation support 280. Further, the light emitting device canfurther include a growth substrate (not illustrated), a wavelengthconverting unit 295, first and second pad electrodes 291 and 293, and astress buffering layer 265.

The light emitting structure 220 can include a region in which a firstconductive type semiconductor layer 221 is partially exposed bypartially removing a second conductive type semiconductor layer 225 andan active layer 223. For example, as illustrated, the light emittingstructure 220 can include a plurality of holes 220 h penetrating throughthe second conductive type semiconductor layer 225 and the active layer223 to expose the first conductive type semiconductor layer 221. Theholes 220 h can be substantially regularly positioned over the entirelight emitting structure 220. However, the present disclosure is notlimited thereto, and other implementations are also possible. That is, aform of the holes 220 h and the number of holes 220 h can be variouslymodified.

In addition, a form in which the first conductive type semiconductorlayer 221 is exposed is not limited to a form such as the hole 220 h.For example, the region in which the first conductive type semiconductorlayer 221 is exposed can be formed in a form such as lines, a combinedholes and lines, or the like.

The second contact electrode 240 can be disposed on the secondconductive type semiconductor layer 225 and ohmic-contact the secondconductive type semiconductor layer 225. The second contact electrode240 can be disposed to generally cover an upper surface of the secondconductive type semiconductor layer 225, and can be disposed to almostcompletely cover the upper surface of the second conductive typesemiconductor layer 225. The second contact electrode 240 can be formedof or include a single body over the entire light emitting structure220. In this case, the second contact electrode 240 can include openingregions corresponding to positions of the plurality of holes 220 h.Therefore, a current is uniformly supplied to the entire light emittingstructure 220, such that current dispersion efficiency can be improved.

However, the present disclosure is not limited thereto, and otherimplementations are also possible. For example, the second contactelectrode 240 can also be formed of a plurality of units.

The first insulating layer 250 can partially cover an upper surface ofthe light emitting structure 220 and the second contact electrode 240.The first insulating layer 250 can cover side surfaces of the pluralityof holes 220 h, and include opening parts partially exposing the firstconductive type semiconductor layer 221 disposed on lower surfaces ofthe holes 220 h. Therefore, the opening parts can be positioned tocorrespond to positions of the plurality of holes 220 h. In addition,the first insulating layer 250 can include opening parts exposingportions of the second contact electrode 240. Further, the firstinsulating layer 250 can further cover at least a portion of a sidesurface of the light emitting structure 220.

The first contact electrode 230 can partially cover the light emittingstructure 220, and ohmic-contact the first conductive type semiconductorlayer 221 through the holes 220 h and the opening parts of the firstinsulating layer 250 that are disposed at portions corresponding to theholes 220 h. In some implementations, the first contact electrode 230can also be formed to cover side surfaces of the light emittingstructure 220.

The second insulating layer 260 can partially cover the first contactelectrode 230, and can include a first opening part 260 a partiallyexposing the first contact electrode 230 and a second opening part 260 bpartially exposing the second contact electrode 240. Each of the firstand second opening parts 260 a and 260 b can be formed in plural. Insome implementations, the opening parts 260 a and 260 b can bepositioned to be closer toward opposing side surfaces.

The stress buffering layer 265 can be disposed on the second insulatinglayer 260.

The first bulk electrode 271 and the second bulk electrode 273 can bedisposed on the light emitting structure 220, and be electricallyconnected to the first contact electrode 230 and the second contactelectrode 240, respectively. The insulation support 280 is disposed onthe light emitting structure 220, and at least partially covers sidesurfaces of the bulk electrodes 271 and 273. In addition, the first andsecond pad electrodes 291 and 293 can be disposed on the first andsecond bulk electrodes 271 and 273, respectively. Since a descriptionfor the insulation support 280 and the first and second pad electrodes291 and 293 is substantially the same as the description provided withreference to FIGS. 19 and 20, a detailed description for the insulationsupport 280 and the first and second pad electrodes 291 and 293 will beomitted.

The wavelength converting unit 295 can be disposed on a lower surface ofthe light emitting structure 220. The light emitting device that canimplement various colors of light by changing a wavelength of the lightemitted from the light emitting structure 220 by the wavelengthconverting unit 210 can be provided. In addition, the wavelengthconverting unit 210 can be formed not only on the lower surface of thelight emitting structure 220, but also extended to side surfaces of thelight emitting structure 220, and can be further extended to sidesurfaces of the insulation support 280.

The wavelength converting unit 295 can include a material that canconvert a wavelength of the light. For example, the wavelengthconverting unit 295 can be provided in a form in which phosphors aredispersed in a carrier, be provided in a single crystalline phosphorsheet form, or be provided in a form in which it includes a quantum dotmaterial. However, the present disclosure is not limited thereto, andother implementations are also possible.

The light emitting device includes the wavelength converting unit 295,thereby making it possible to provide a chip scale package that can emitwhite light.

FIG. 25 to FIG. 39 are plan views and cross-sectional views fordescribing exemplary light emitting devices and exemplary methods ofmanufacturing the same according to some embodiments of the presentdisclosure. In the respective drawings, (a) and (b) included in the samedrawing indicate a plan view and a cross-sectional view, respectively,and (b) in each drawing illustrates a cross section taken along lineV-V′ of (a). In the following description, light emitting devices andmethods of manufacturing the same according to various exemplaryembodiments of the present disclosure will be described with referenceto FIG. 25(a) to FIG. 39(b). A detailed description for configurationssimilar to the configurations described in the exemplary embodiments ofFIGS. 1 to 14(b) will be contracted or omitted, and configurationsdifferent from the configurations described in the exemplary embodimentsof FIGS. 1 to 14(b) will be described in detail. In addition, inexemplary embodiments to be described below, even in the case ofdescribing a method of manufacturing a light emitting device based on asingle light emitting device, configurations and features described inthe above exemplary embodiments can also be applied to the case offorming a plurality of light emitting devices.

Referring to FIGS. 25(a) and 25(b), a light emitting structure 220including a first conductive type semiconductor layer 221, an activelayer 223, and a second conductive type semiconductor layer 225 isformed on a growth substrate 210.

The growth substrate 210 is not limited as long as the light emittingstructure 220 can be grown over the growth substrate 210. For example,the growth substrate 210 can be or include a sapphire substrate, asilicon carbide substrate, a silicon substrate, a gallium nitridesubstrate, or an aluminum nitride substrate, or the like. The lightemitting structure 220 can be grown using a method such as metal organicchemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE),or molecular beam epitaxy (MBE), or the like.

In addition, although the growth substrate 210 and the light emittingstructure 220 corresponding to the single device have been illustratedin FIGS. 25(a) and 25(b), the present exemplary embodiment can besubstantially similarly applied to the case of using a wafer having thelight emitting structure 220 grown on the growth substrate 210.

Then, referring to FIGS. 26(a) and 26(b), the light emitting structure220 is patterned to form at least one mesa 220 m.

The mesa 220 m can be formed by partially removing the second conductivetype semiconductor layer 225 and the active layer 223 byphotolithography and etching processes. The mesa 220 m is formed, suchthat the first conductive type semiconductor layer 221 can be partiallyexposed in a peripheral region of the mesa 220 m. The mesa 220 m doesnot have a limited form, but can have a form in which it is extended insubstantially the same direction, as illustrated in FIG. 26(a). In someimplementations, the mesas 220 m can be formed in plural. In this case,the plurality of mesas 220 m can be spaced apart from each other.

However, the present disclosure is not limited thereto, and otherimplementations are also possible. For example, as illustrated in FIGS.27(a) and 27(b), the mesa 220 m can also have a form in which it isintegrally formed and includes portions depressed from one side surfacethereof. For example, as illustrated in FIG. 27(a), a mesa 220 m′ canhave a form in which portions thereof adjacent to one side surface ofthe growth substrate 110 are connected to each other and spaced regionsare formed in portions thereof adjacent to the other side surface of thegrowth substrate 110 positioned to be opposite to one side surface. Thefirst conductive type semiconductor layer 221 can be partially exposedthrough the spaced regions. The number of spaced regions can be plural.For example, FIG. 27(a) show two spaced regions and FIG. 27(b) showthree spaced regions. In some implementations, more than three spacedregions can be formed. In some implementations, the mesa 220 m can alsohave a form in which it includes a plurality of grooves partiallyexposing the first conductive type semiconductor layer 221. In thiscase, the light emitting structure 220 having a form similar to those ofthe exemplary embodiment of FIGS. 8A to 9B can be provided.

Next, referring to FIGS. 28(a) and 28(b), second contact electrodes 240are formed on the second conductive type semiconductor layer 225, forexample, at least portions of upper surfaces of the mesas 220 m.Further, preliminary first insulating layers 251 can be further formedon the light emitting structure 220.

The second contact electrode 240 can include at least one of a metal ora conductive oxide, as described above. The second contact electrodes240 can be formed to be disposed on at least portions of the uppersurfaces of the mesas 220 m through suitable depositing and patterningmethods.

The preliminary first insulating layers 251 can be formed on the lightemitting structure 220, and be formed to at least partially cover theupper surface of the light emitting structure 220 except for regions inwhich the second contact electrodes 240 are formed. The preliminaryfirst insulating layers 251 can cover exposed regions of the firstconductive type semiconductor layer 221. Further, the preliminary firstinsulating layers 251 can further cover side surfaces of the mesas 220m. Further, the preliminary first insulating layers 251 can partiallycover upper surfaces of the mesas 220 m. The preliminary firstinsulating layers 251 can contact the second contact electrodes 240 orbe spaced apart from the second contact electrodes 240. In the case inwhich the preliminary first insulting layers 251 are spaced apart fromthe second contact electrodes 240, the second conductive typesemiconductor layer 225 is partially exposed between the preliminaryfirst insulting layers 251 and the second contact electrodes 240. Thepreliminary first insulting layer 251 can include SiO₂, SiN_(x), orMgF₂, and the like. Further, the preliminary first insulating layer 251can include multiple layers, and include a distributed Bragg reflectorin which materials having different refractive indices are alternatelystacked.

Meanwhile, the preliminary first insulating layer 251 can be formedbefore the second contact electrode 240 is formed, be formed after thesecond contact electrode 240 is formed, or be formed during a period inwhich the second contact electrode 240 is formed. For example, in thecase in which the second contact electrode 240 includes a conductiveoxide layer and a reflecting layer disposed on the conductive oxidelayer and including a metal, the preliminary first insulating layer 251can be formed after the conductive oxide layer is formed on the secondconductive type semiconductor layer 225 and before the reflecting layeris formed. In this case, the conductive oxide layer ohmic-contacts thesecond conductive type semiconductor layer 225, and the preliminaryfirst insulating layer 251 can be formed at a thickness of about 1000 Å.In another exemplary embodiment, the preliminary first insulating layer251 can be formed before the second contact electrode 240 is formed. Inthis case, the second contact electrode 240 can form an ohmic-contactwith the second conductive type semiconductor layer 225, and include areflecting layer made of a metal material. In these exemplaryembodiments, the preliminary first insulating layer 251 is formed beforethe reflecting layer including the metal material is formed, therebymaking it possible to prevent a decrease in light reflectivity and anincrease in a resistance of the reflecting layer due to diffusion ofmaterials between the reflecting layer and the light emitting structure220. In addition, a problem such as an electric short-circuit that canbe generated due to the metal material remaining in other portions inwhich the second contact electrodes 240 are not formed in a process offorming the reflecting layer including the metal material can beprevented.

Then, referring to FIGS. 29(a) and 29(b), a first insulating layer 250is formed on the light emitting structure 220. The first insulatinglayers 250 partially cover the first conductive type semiconductor layer221, the mesas 220 m, and the second contact electrodes 240. Inaddition, the first insulating layer 250 can include first opening parts250 a partially exposing the first conductive type semiconductor layer221 and second opening parts 250 b partially exposing the second contactelectrodes 240.

The first insulating layer 250 can include the preliminary firstinsulating layer 251 described with reference to FIGS. 28(a) and 28(b)and a main first insulating layer 253. The main first insulating layer253 can be formed through a suitable deposition method such as plasmaenhanced chemical vapor deposition (PECVD), or E-beam evaporation, orthe like. Here, after the main first insulating layer 253 is formed togenerally cover the first conductive type semiconductor layer 221, themesas 220 m, and the second contact electrodes 240, the first and secondopening parts 250 a and 250 b are formed through a patterning process,thereby making it possible to provide the first insulating layer 250 asillustrated. The patterning process can include a photolithographyprocess, or a lift-off process. The main first insulting layer 253 caninclude SiO₂, SiN_(x), or MgF₂, and the like. Further, the main firstinsulating layer 253 can include multiple layers, and include adistributed Bragg reflector in which materials having differentrefractive indices are alternately stacked. In addition, the main firstinsulating layer 253 can have a thickness greater than that of thepreliminary first insulating layer 251.

The number of first opening parts 250 a can be at least one. Forexample, the first opening parts 250 a can be formed on the mesas 220 m,respectively. In some implementations, the first opening part 250 a canbe formed at a position adjacent to one side surface of the growthsubstrate 210. The second opening parts 250 b can have a shape in whichthey are extended along a direction in which the mesas 220 m areextended. In some implementations, the second opening parts 250 b can beformed adjacent to long side surfaces of the mesas 220 m. However,positions, sizes, and the numbers of the first and second opening parts250 a and 250 b are not limited thereto, and other implementations arealso possible, but can be variously modified depending on positions atwhich bulk electrodes 271 and 273 to be described below are formed, orthe like.

Meanwhile, although the case in which the second contact electrodes 240are formed after the mesas 220 m are formed has been described, themesas 220 m can be formed after the second contact electrodes 240 areformed.

Next, referring to FIGS. 30(a) and 30(b), a first contact electrode 230is formed on the first insulating layer 250. The first contact electrode230 can ohmic-contact the first conductive type semiconductor layer 221exposed through the first opening parts 250 a. Further, a connectingelectrode 245 electrically contacting the second contact electrode 240through the second opening part 250 b can be further formed.

The first contact electrode 230 and the connecting electrode 245 can beformed through the known depositing and patterning method, and besimultaneously formed or be formed through separate processes. The firstcontact electrode 230 and the connecting electrode 245 can be formed ofor include the same material and in a multilayer structure or be formedof different materials and/or in a multilayer structure. The firstcontact electrode 230 and the connecting electrode 245 are spaced apartfrom each other, such that the first and second contact electrodes 230and 240 are electrically insulated from each other.

For example, the first contact electrode 230, or the connectingelectrode 245, or the both can include a multilayer structure. Themultilayer structure can have a stack structure including first adheringlayer (ohmic contact layer), reflecting layer, barrier layer, oxidationpreventing layer, and second adhering layer. The first adhering layercan contact the first conductive type semiconductor layer 221, thesecond contact electrode 240, or the both, and include Ni, Ti, or Cr, orthe like. The reflecting layer can include a metal having highreflectivity, for example, Al, or Ag, or the like. The barrier layer canprevent mutual diffusion of a metal of the reflecting layer, be formedof a single layer of Cr, Co, Ni, Pt, or TiN, or be formed of multiplelayers of Cr, Co, Ni, Pt, or TiN together with Ti, Mo, or W, forexample, can have a plural layer structure of Cr/Ti. The oxidationpreventing layer can prevent oxidation of other layers positionedtherebelow, and include a metal material having strong resistance tooxidation. The oxidation preventing layer can include, for example, Au,Pt, or Ag, or the like. The second adhering layer can be adopted inorder to improve adhesion between a second insulating layer 260 and thefirst conductive type semiconductor layer 221 (or between the secondinsulating layer 260 and the connecting electrode 245), and can include,for example, Ti, Ni, or Cr, or the like. However, the present disclosureis not limited thereto, and other implementations are also possible.

In some implementations, the connecting electrode 245 can also beomitted. As illustrated in FIGS. 30(a) and 30(b), in the case in whichthe connecting electrode 245 is omitted, the second contact electrode240 is exposed through the second opening part 250 b. Therefore, in thiscase, a second bulk electrode 173 can directly contact the secondcontact electrode 240.

Then, referring to FIGS. 31(a) and 31(b), a second insulating layer 260partially covering the first contact electrode 230 and the connectingelectrode 245 is formed. The second insulating layer 260 can includethird and fourth opening parts 260 a and 260 b each exposing the firstcontact electrode 230 and the connecting electrode 245. Further, astress buffering layer 265 can be further formed on the secondinsulating layer 260.

The second insulating layer 260 can be formed through the knowndeposition method such as plasma enhanced chemical vapor deposition(PECVD), or E-beam evaporation, or the like. Here, after the secondinsulating layer 260 is formed to generally cover the first contactelectrode 230 and the connecting electrode 245, the third and fourthopening parts 260 a and 260 b are formed in the second insulating layer260 through a patterning process, such that the second insulating layer260 as illustrated can be provided. The patterning process can include aphotolithography process, or a lift-off process. The second insultinglayer 260 can include SiO₂, SiN_(x), or MgF₂, and the like. Further, thesecond insulating layer 260 can include multiple layers, and include adistributed Bragg reflector in which materials having differentrefractive indices are alternately stacked. The uppermost layer of thesecond insulating layer 260 can be formed of or include SiN_(x). Theuppermost layer of the second insulating layer 260 is made of orincludes SiN_(x), thereby making it possible to more effectively preventmoisture from permeating into the light emitting structure 220. Inaddition, the second insulating layer 260 can have a thickness thinnerthan that of the first insulating layer 250, and can have a thickness ofabout 0.8 μm in order to secure an insulation withstand voltage.However, the present disclosure is not limited thereto, and otherimplementations are also possible.

The third and fourth opening parts 260 a and 260 b expose the firstcontact electrode 230 and the connecting electrode 245, respectively,thereby making it possible to provide paths through which bulkelectrodes 171 and 173 can be electrically connected to the firstcontact electrode 230 and the second contact electrode 240.

The stress buffering layer 265 can be formed through a method such as adepositing method, a spin coating method, or the like, and be patternedtogether with the second insulating layer 260. Therefore, the stressbuffering layer 265 can include opening parts formed at positionscorresponding to those of the third and fourth opening parts 260 a and260 b.

Referring to FIG. 33(a) to FIG. 34(b), a first bulk electrode 271, asecond bulk electrode 273, and a lower insulation support 283 are formedon the second insulating layer 260.

Referring to FIGS. 33(a) and 33(b), regions in which first and secondbulk electrodes 271 and 273 are formed are defined using a mold 310 forforming bulk electrodes, such that the first and second bulk electrodes271 and 273 can be formed. The mold 310 for forming bulk electrodes canbe or include a mold that can be patterned, and can include, forexample, photosensitive polyimide, SU-8, a photo-resist for plating, ora dry film.

The first and second bulk electrodes 271 and 273 can be formed using aplating method, a depositing method, a dotting method, or a screenprinting method, or the like. Forming the first and second bulkelectrodes 271 and 273 can include forming first and second metal layers271 s and 273 s. The first and second metal layers 271 s and 273 s canbe positioned below the first and second bulk electrodes 271 and 273,respectively, to contact the first contact electrode 230, the connectingelectrode 245, the insulating layers 250 and 260, and the stressbuffering layer 265. The first and second metal layers 271 s and 273 scan be changed depending on a method of forming the bulk electrodes 271and 273.

Referring to FIGS. 34(a) and 34(b), the mold 310 for forming bulkelectrodes is removed, and a lower insulation support 283 at leastpartially covering side surfaces of the first and second bulk electrodes271 and 273 is formed. The lower insulation support 283 can be formedand provided by performing the available techniques such as a screenprinting method or a spin coating method on a material such as an epoxymolding compound (EMC) or a Si resin.

The method of manufacturing a light emitting device according to thepresent exemplary embodiment can further include planarizing uppersurfaces of the first and second bulk electrodes 271 and 273 and thelower insulation support 283 after forming the lower insulation support283. Therefore, the upper surfaces of the first and second bulkelectrodes 271 and 273 can be formed to be substantially flush with thelower insulation support 283. The planarizing of the first and secondbulk electrodes 271 and 273 and the lower insulation support 283 caninclude using at least one of a grinding method, a lapping method, achemical mechanical polishing (CMP) method, or a wet etching.

Next, a process of forming the first and second bulk electrodes 271 and273 and the lower insulation support 283 will be described in moredetail. In the case in which the first and second bulk electrodes 271and 273 are formed using plating, the first and second metal layers 271s and 273 s are formed over entire surfaces of the stress bufferinglayer 265, the third opening part 260 a, and the fourth opening part 260b by a method such as a sputtering method. The first and second metallayers 271 s and 273 s can include Ti, Cu, Au, or Cr, or the like, andserve as an under bump metallization (UMB) layer or a seed metal. Forexample, the first and second metal layers 271 s and 273 s can have astack structure including Ti/Cu. Then, a mask is formed on the first andsecond metal layers 271 s and 273 s. Here, the mask can be the mold 310for forming bulk electrodes. The mold 310 for forming bulk electrodesmasks a portion corresponding to a region in which the lower insulationsupport 283 is formed and opens regions in which the first and secondbulk electrodes 271 and 273 are formed. Next, the first and second bulkelectrodes 271 and 273 are formed in the opened regions of the maskthrough a plating process. Here, the first and second bulk electrodes271 and 273 can be formed using the first and second metal layers 271 sand 273 s as seeds, respectively. Then, the mold 310 for forming bulkelectrodes and portions of the first and second bulk electrodes 271 and273 positioned below the mold 310 for forming bulk electrodes areremoved through an etching process, such that the first and second bulkelectrodes 271 and 273 can be provided. Therefore, the first and secondmetal layers 271 s and 273 s can remain below the first and second bulkelectrodes 271 and 273, respectively.

The case in which the first and second bulk electrodes 271 and 273 areformed using the screen printing method will be described. A UBM layeris formed on at least portions of the stress buffering layer 265, thethird opening part 260 a, and the fourth opening part 260 b through adepositing and patterning method such as a sputtering method or adepositing and lift-off method. The UBM layer can be formed on regionsin which the first and second bulk electrodes 271 and 273 are to beformed, and can include a (Ti or TiW) layer and a single layer includingCu, Ni, or Au or a combination layer thereof. For example, the UBM layercan have a stack structure of Ti/Cu. The UBM layer can correspond to thefirst and second metal layers 271 s and 273 s. Then, a mask is formed.The mask masks a portion corresponding to a region in which the lowerinsulation support 283 is formed and opens regions in which the firstand second bulk electrodes 271 and 273 are formed. Then, a material suchas an Ag paste, an Au paste, or a Cu paste is formed in the open regionsthrough a screen printing process and is hardened. Next, the mask isremoved through an etching process, such that the first and second bulkelectrodes 271 and 273 can be provided.

The first bulk electrode 271 includes a first protrusion part 271 sprotruding from a side surface of the first bulk electrode 271 facingthe second bulk electrode 273, and a second protrusion part 271 bfurther protruding from the first protrusion part 271 a toward thesecond bulk electrode 273. The second bulk electrode 273 includes afirst concave part 273 a depressed from a side surface of the secondbulk electrode 273 facing the first bulk electrode 271, and a secondconcave part 273 b depressed from the first concave part 273 a.Therefore, the horizontal cross-sectional area of the first bulkelectrode 271 can be greater than that of the second bulk electrode 273.

In addition, the protrusion parts 271 a and 271 b are formed to beengaged with the concave parts 273 a and 273 b, respectively. The firstprotrusion part 271 a can be positioned to correspond to a portiondepressed by the first concave part 273 a, and the second protrusionpart 271 b can be positioned to correspond to a portion depressed by thesecond concave part 273 b. Therefore, a spaced distance between sidesurfaces of the first and second bulk electrodes 271 and 273 facing eachother can be maintained to be substantially constant. Further, thesecond protrusion part 271 b can have a width smaller than that of thefirst protrusion part 271 a.

The second protrusion part 271 b can have various shapes, and can beformed of or include at least a portion of a polygon, a circle, or anellipse having an inscribed circle 200 ic whose center is located at acentral portion 200 c of the light emitting device and diameter is about50 μm or more to 150 μm or less. For example, as illustrated, the secondprotrusion part 271 b can have a shape including an arc corresponding tothe inscribed circle 200 ic whose center is located at the centralportion 200 c of the light emitting device. The first and second concaveparts 273 a and 273 b can have shapes corresponding to those of thefirst and second protrusion parts 271 a and 271 b.

A virtual line D6-D6′ extended along a spaced region of a portion atwhich the first and second bulk electrodes 271 and 273 face each othercan have one or more bending portions. Although the virtual line D6-D6′having the one or more bending portions can be derived from shapes andlayouts of the protrusion parts 271 a and 271 b and the concave parts273 a and 273 b, the present disclosure is not limited thereto, andother implementations are also possible. A starting point and an endingpoint of the virtual line D6-D6′ can be disposed on the same line.

Meanwhile, the protrusion parts 271 a and 271 b of the first bulkelectrode 271 can overlap with the central portion 200 c of the lightemitting device in the vertical direction. In the present exemplaryembodiment, the second protrusion part 271 b is shaped to have at leasta portion of the polygon, the circle, or the ellipse having theinscribed circle 200 ic of which the origin or center is located at thecentral portion 200 c of the light emitting device. In this case, thecenter of the inscribed circle 200 icis positioned to be overlapped withthe central portion 200 c of the light emitting device in the verticaldirection. Therefore, generation of a crack in the insulation support280 and damage to the insulation support 280 in a process ofmanufacturing the light emitting device can be prevented, therebyimproving a manufacturing yield of the light emitting device. This willbe described below in more detail. In addition, the protrusion parts 271a and 271 b are overlapped with the central portion 200 c of the lightemitting device in the vertical direction, thereby making it possible toeffectively prevent the crack and the damage of the insulation support280. Therefore, strength of the light emitting device against externalimpact can be improved, and strength against a warpage momentum due tostress, or the like, applied from the outside can be further improved.For example, a peripheral region of the central portion 200 c of thelight emitting device in the vertical direction is covered with thefirst bulk electrode 271, thereby making it possible to more effectivelyimprove mechanical stability of the light emitting device.

Then, referring to FIGS. 35(a) and 35(b), a first pad electrode 291, asecond pad electrode 293, and an upper insulation support 281 can befurther formed on the lower insulation support 283 and the bulkelectrodes 271 and 273.

The first and second pad electrodes 291 and 293 can be formed on thefirst and second bulk electrodes 271 and 273, respectively, throughdepositing and patterning processes. The upper insulation support 281can enclose side surfaces of the first and second pad electrodes 291 and293. The upper insulation support 281 is formed, such that theinsulation support 280 including the upper insulation support 281 andthe lower insulation support 283 can be provided. The upper insulationsupport 281 can be formed of or include the same material as that of thelower insulation support 283 or be made of or include a materialdifferent from that of the lower insulation support 283.

Next, referring to FIG. 36, the growth substrate 210 can be separatedfrom the light emitting structure 220. The growth substrate 210 can beseparated and removed from the first conductive type semiconductor layer221 using at least one of a laser lift-off method, a chemical lift-offmethod, a thermal lift-off method, or a stress lift-off method. Afterthe growth substrate 210 is separated, a surface of the first conductivetype semiconductor layer 221 exposed by separating the growth substrate210 can be partially removed through at least one of a dry etchingmethod, a wet etching method, a physical method, a chemical method, or aphysicochemical method.

Meanwhile, a temporary substrate (not illustrated) can be bonded to anopposite side of the growth substrate 210 before the growth substrate210 is removed. In a process of separating the growth substrate 210, thetemporary substrate serves to support the light emitting device.Therefore, generation of a defect in the light emitting device due tostress and strain generated in the process of separating the growthsubstrate 210 can be suppressed. For example, in the case in which thegrowth substrate is separated into a large area in a wafer unit in orderto manufacture a plurality of light emitting devices, it is likely thata crack or damage will be generated in the light emitting structure 220,or the like, in the process of separating the growth substrate 210 tocause a defect in the light emitting device. The temporary substrate canprevent, for example, the defect of the light emitting device in thiscase. For example, as illustrated in FIGS. 37(a) and 37(b), in the caseof manufacturing a plurality of light emitting devices, a temporarysubstrate 320 can be used.

In the case of manufacturing the plurality of light emitting devices ina wafer unit, portions between unit device regions can be partiallyremoved after the growth substrate 210 is separated. As illustrated inFIG. 37(a), in the case of manufacturing the plurality of light emittingdevices, a wafer W1 from which the growth substrate 210 is separated canbe disposed on the temporary substrate 320. Here, the wafer W1 caninclude a plurality of unit devices UD, and a boundary L1 between theplurality of unit devices UD can be defined as a separation region 331.As illustrated in FIG. 37(b), the separation region 331 is partiallyremoved, such that a separation groove 333 can be formed between theplurality of unit devices UD. The separation groove 333 can be formed byat least partially removing the first conductive type semiconductorlayer 221 through a method such as a dry etching method. Before thewafer W1 is separated into unit light emitting devices, the separationgroove 333 in which the first conductive type semiconductor layer 221 ispartially removed is formed, thereby making it possible to preventgeneration of chipping or a crack in the light emitting structure 220 ina process of separating the wafer W1 into the unit light emittingdevices. However, a process of forming the separation groove 333 canalso be omitted.

Then, referring to FIG. 38, a wavelength converting unit 295 can beformed on the light emitting structure 220. In addition, before thewavelength converting unit 295 is formed, a rough surface 220R can befurther formed by increasing a roughness of a surface of the lightemitting structure 220. Therefore, the light emitting device asillustrated in FIG. 38 can be provided.

The wavelength converting unit 295 can include a material that canconvert a wavelength of the light. For example, the wavelengthconverting unit 295 can be provided in a form in which phosphors aredispersed in a carrier, be provided in a single crystalline phosphorsheet form, or be provided in a form in which it includes a quantum dotmaterial. However, the present disclosure is not limited thereto, andother implementations are also possible. The light emitting deviceaccording to the present exemplary embodiment includes the wavelengthconverting unit 295, thereby making it possible to provide a chip scalepackage that can emit white light. The wavelength converting unit 295can not only be formed on the upper surface of the light emittingstructure 220, but can also be extended to side surfaces of the lightemitting structure 220, and can be further extended to side surfaces ofthe insulation support 280. The wavelength converting unit 295 can beformed through applying and hardening methods, a spray method, or otherknown methods.

The rough surface 220R can be formed by at least one of a wet etchingmethod, a dry etching method, or an electrochemical etching method, andcan be formed using, for example, a photo-electrochemical (PEC) etchingmethod, an etching method using an etching solution including KOH orNaOH, or the like. Therefore, the light emitting structure 220 caninclude protrusion parts, concave parts, or the both formed on a surfaceof the first conductive type semiconductor layer 221 and having a scaleof μm to nm. Light extracting efficiency of light emitted by the lightemitting structure 220 can be improved by the rough surface 220R.

Meanwhile, after the wavelength converting unit 295 is formed, apassivation layer (not illustrate) at least partially covering a surfaceof the light emitting device can be further formed.

Meanwhile, the light emitting device illustrated in FIG. 38 can bemanufactured from a wafer W2 including a plurality of unit devices UD.Referring to FIGS. 39(a) to 39(c), as illustrated in FIG. 39(a), thewafer W2 including the plurality of unit devices UD bonded to atemporary substrate 320 can be prepared. The wafer W2 can be disposed ona first support 340 for a separation process. The first support 340 caninclude a dicing tape. Then, referring to FIG. 39(b), the temporarysubstrate 320 is separated from the wafer W2, and the wafer W2 is dicedalong a separation line L2. The separation line L2 corresponds to aboundary between the plurality of unit devices UD. Next, the pluralityof unit devices UD separated in the plural can be picked up and betransferred from the first support 340 to a second support 340 a inorder to perform the next process. The second support 340 a can alsoinclude a dicing tape. Here, as illustrated in FIG. 39(c), in the casein which the second support 340 a is the dicing tape, picking up oneunit device UD1 can include pushing the one unit device UD1 upwardlyusing an ejector pin 350 below the dicing tape (the second support 340a).

In this process, the ejector pin 350 applies impact to a portion of alower portion of the light emitting device. As illustrated in FIG. 39©and FIGS. 40(a) and 40(b), stress can be propagated from a portion PP towhich impact is applied by a pin point of the ejector pin 350 along avertical direction C1. Therefore, the stress can be concentrated onregions overlapped with the portion PP to which the impact is applied bythe pin point of the ejector pin 350 in the vertical direction C1. Here,the portion PP to which the impact is applied by the pin point cansubstantially coincide with the central portion 200 c of the lightemitting device. In the case in which the insulation support 280 isdisposed at a portion overlapped with the central portion 200 c of thelight emitting device in the vertical direction C1, particularly in thecase in which a portion of the insulation support 280 disposed betweenthe first and second bulk electrodes 271 and 273 is overlapped with thecentral portion 200 c of the light emitting device in the verticaldirection C1, a crack is easily generated in the insulation support 280,such that a defect can be generated in the manufactured light emittingdevice. According to the present exemplary embodiment, as illustrated inFIGS. 40(a) and 40(b), the first bulk electrode 271, for example, theprotrusion parts 271 a and 271 b can be disposed at the portionoverlapped with the central portion 200 c (substantially correspondingto the portion PP to which the impact is applied by the pin point) ofthe light emitting device in the vertical direction C1, thereby makingit possible to effectively prevent a defect of the insulation support280 by the ejector pin 350. In addition, in the case in which the secondprotrusion part 271 b is formed of the polygon, the circle, or theellipse having the inscribed circle 200 ic of which the origin is thecentral portion 200 c of the light emitting device and the diameter isabout 50 μm or more, stress generated due to impact by the ejector pin350 is absorbed and relaxed, thereby making it possible to moreeffectively prevent generation of a defect due to the stress applied tothe insulation support 280.

In addition, according to the present exemplary embodiment, a lightemitting device having excellent mechanical stability and high heatradiation efficiency can be provided.

According to various embodiments of the present disclosure, the growthsubstrate is separated, such that the light efficiency and the heatradiation efficiency of the light emitting device can be improved. Inaddition, the light emitting device according to the present disclosureincludes a support member on which pads are formed while substitutingfor a secondary substrate in a wafer level, thereby making it possibleto secure structural stability without the growth substrate and thesecondary substrate. Further, the light emitting device according to thepresent disclosure can prevent diffusion of a metallic element in thesolder paste, such that it can be directly mounted on the printedcircuit board using the solder paste. In addition, with a method ofmanufacturing the light emitting device according to the presentdisclosure, the light emitting device having the above-mentioned effectscan be manufactured.

In addition, the light emitting device including the first and secondbulk electrodes each having the protrusion part and the concave part isprovided. Therefore, the generation of the delamination phenomenonbetween the bulk electrodes and the insulation support can besuppressed, and the mechanical stability of the insulation support isimproved, thereby making it possible to improve the reliability of thelight emitting device. In addition, the light emitting device havingimproved heat radiation efficiency by forming the bulk electrodes so asto have different horizontal cross-sectional areas is provided.

Further, the protrusion part of the first bulk electrode is disposed atthe position overlapped with the central portion of the light emittingdevice in the vertical direction, such that the mechanical stability ofthe light emitting device can be improved, and the generation of thedefect or damage in the insulation support in the process ofmanufacturing the light emitting device is effectively prevented, suchthat the manufacturing yield of the light emitting device can beimproved. FIG. 36 is an exploded perspective view of an exemplarylighting apparatus to which a light emitting device according to someembodiments of the present disclosure is applied.

Referring to FIG. 41, the lighting apparatus according to thisembodiment includes a diffusive cover 1010, a light emitting diodemodule 1020, and a body 1030. The body 1030 can receive the lightemitting diode module 1020 and the diffusive cover 1010 can be disposedon the body 1030 to cover an upper side of the light emitting diodemodule 1020.

The body 1030 can have any shape so long as the body can supply electricpower to the light emitting diode module 1020 while receiving andsupporting the light emitting diode module 1020. For example, as shownin the drawing, the body 1030 can include a body case 1031, a powersupply 1033, a power supply case 1035, and a power source connectionsection 1037.

The power supply 1033 is received in the power supply case 1035 to beelectrically connected to the light emitting diode module 1020, and caninclude at least one IC chip. The IC chip can regulate, change orcontrol electric power supplied to the light emitting diode module 1020.The power supply case 1035 can receive and support the power supply1033. The power supply case 1035 having the power supply 1033 securedtherein can be disposed within the body case 1031. The power sourceconnection section 1037 is disposed at a lower end of the power supplycase 1035 and coupled thereto. Accordingly, the power source connectionsection 1037 is electrically connected to the power supply 1033 withinthe power supply case 1035 and can serve as a passage through whichpower can be supplied from an external power source to the power supply1033.

The light emitting diode module 1020 includes a substrate 1023 and alight emitting diode 1021 disposed on the substrate 1023. The lightemitting diode module 1020 can be disposed at an upper portion of thebody case 1031 and electrically connected to the power supply 1033.

As the substrate 1023, any substrate capable of supporting the lightemitting diode 1021 can be used without limitation. For example, thesubstrate 1023 can include a printed circuit board having interconnectsformed thereon. The substrate 1023 can have a shape corresponding to asecuring portion formed at the upper portion of the body case 1031 so asto be stably secured to the body case 1031. The light emitting diode1021 can include at least one of the light emitting diodes and the lightemitting devices according to the embodiments described above.

The diffusive cover 1010 is disposed on the light emitting diode 1021and can be secured to the body case 1031 to cover the light emittingdiode 1021. The diffusive cover 1010 can be formed of or include alight-transmitting material, and light orientation of the lightingapparatus can be adjusted through regulation of the shape and opticaltransmissivity of the diffusive cover 1010. As such, the diffusive cover1010 can be modified in various shapes depending on usage andapplications of the lighting apparatus.

FIG. 42 is a sectional view of an exemplary display device to which alight emitting device according to some embodiments of the presentdisclosure is applied.

The display device according to this embodiment includes a display panel2110, a backlight unit supplying light to the display panel 2110, and apanel guide supporting a lower edge of the display panel 2110.

The display panel 2110 is not particularly limited and can be, forexample, a liquid crystal panel including a liquid crystal layer. Gatedriving PCBs can be further disposed at the edge of the display panel2110 to supply driving signals to a gate line. Here, the gate drivingPCBs 2112 and 2113 can be formed on a thin film transistor substrateinstead of being formed on separate PCBs.

The backlight unit includes a light source module, which includes atleast one substrate and a plurality of light emitting diodes 2160. Thebacklight unit can further include a bottom cover 2180, a reflectivesheet 2170, a diffusive plate 2131, and optical sheets 2130.

The bottom cover 2180 can be open at an upper side thereof to receivethe substrate, the light emitting diodes 2160, the reflective sheet2170, the diffusive plate 2131, and the optical sheets 2130. Inaddition, the bottom cover 2180 can be coupled to the panel guide Thesubstrate can be disposed under the reflective sheet 2170 to besurrounded by the reflective sheet 2170. However, it should beunderstood that other implementations are also possible. When areflective material is coated onto a surface thereof, the substrate canbe disposed on the reflective sheet 2170. Further, in this embodiment, aplurality of substrates can be arranged parallel to one other. However,it should be understood that other implementations are also possible andthe light source module can include a single substrate.

The light emitting diodes 2160 can include at least one of the lightemitting diodes and the light emitting devices according to theembodiments described above. The light emitting diodes 2160 can beregularly arranged in a predetermined pattern on the substrate. Inaddition, a lens 2210 is disposed on each of the light emitting diodes2160 to improve uniformity of light emitted from the plurality of lightemitting diodes 2160.

The diffusive plate 2131 and the optical sheets 2130 are disposed on thelight emitting devices 2160. Light emitted from the light emittingdevices 2160 can be supplied in the form of sheet light to the displaypanel 2110 through the diffusive plate 2131 and the optical sheets 2130.

In this way, the light emitting diodes according to the embodiments ofthe present disclosure can be applied to direct type displays like thedisplay according to this embodiment.

FIG. 43 is a sectional view of an exemplary display device to which alight emitting device according to some embodiments of the presentdisclosure is applied.

The display device according to this embodiment includes a display panelon which an image is displayed, and a backlight unit disposed at a rearside of the display panel 3210 and emitting light thereto. Further, thedisplay device includes a frame 240 supporting the display panel 3210and receiving the backlight unit, and covers 3240 and 3280 surroundingthe display panel 3210.

The display panel 3210 is not particularly limited and can be orinclude, for example, a liquid crystal panel including a liquid crystallayer. A gate driving PCB can be further disposed at an edge of thedisplay panel 3210 to supply driving signals to a gate line. Here, thegate driving PCB can be formed on a thin film transistor substrateinstead of being formed on a separate PCB. The display panel 3210 issecured by the covers 3240 and 3280 disposed at upper and lower sidesthereof, and the cover 3280 disposed at the lower side of the displaypanel 3210 can be coupled to the backlight unit.

The backlight unit supplying light to the display panel 3210 includes alower cover 3270 partially open at an upper side thereof, a light sourcemodule disposed at one side inside the lower cover 3270, and a lightguide plate 3250 disposed parallel to the light source module andconverting spot light into sheet light. In addition, the backlight unitaccording to this embodiment can further include optical sheets 3230disposed on the light guide plate 3250 to spread and collect light, anda reflective sheet 3260 disposed at a lower side of the light guideplate 3250 and reflecting light traveling in a downward direction of thelight guide plate 3250 towards the display panel 3210.

The light source module includes a substrate 3220 and a plurality oflight emitting diodes 3110 arranged at constant intervals on one surfaceof the substrate 3220. As the substrate 3220, any substrate capable ofsupporting the light emitting diodes 3110 and being electricallyconnected thereto can be used without limitation. For example, thesubstrate 3220 can include a printed circuit board.

The light emitting diodes 3110 can include at least one of the lightemitting diodes and the light emitting devices according to theembodiments of the present disclosure described above. Light emittedfrom the light source module enters the light guide plate 3250 and issupplied to the display panel 3210 through the optical sheets 3230. Thelight guide plate 3250 and the optical sheets 3230 convert spot lightemitted from the light emitting diodes 3110 into sheet light.

In this way, the light emitting diodes according to the embodiments canbe applied to edge type displays like the display according to thisembodiment.

FIG. 44 is a sectional view of an exemplary headlight to which a lightemitting device according to some embodiments of the present disclosureis applied.

Referring to FIG. 44, the headlight includes a lamp body 4070, asubstrate 4020, a light emitting diode 4010, and a cover lens 4050. Theheadlight can further include a heat dissipation unit 4030, a supportrack 4060, and a connection member 4040.

The substrate 4020 is secured by the support rack 4060 and disposedabove the lamp body 4070. As the substrate 4020, any member capable ofsupporting the light emitting diode 4010 can be used without limitation.For example, the substrate 4020 can be or include a substrate having aconductive pattern, such as a printed circuit board. The light emittingdiode 4010 is disposed on the substrate 4020 and can be supported andsecured by the substrate 4020. In addition, the light emitting diode4010 can be electrically connected to an external power source throughthe conductive pattern of the substrate 4020. Further, the lightemitting diode 4010 can include at least one of the light emittingdiodes and the light emitting devices according to the embodiments ofthe present disclosure described above.

The cover lens 4050 is disposed on a path of light emitted from thelight emitting diode 4010. For example, as shown in the drawing, thecover lens 4050 can be spaced apart from the light emitting diode 4010by the connection member 4040 and can be disposed in a direction ofsupplying light emitted from the light emitting diode 4010. By the coverlens 4050, an orientation angle and/or a color of light emitted by theheadlight can be adjusted. On the other hand, the connection member 4040is disposed to secure the cover lens 4050 to the substrate 4020 whilesurrounding the light emitting diode 4010, and thus can act as a lightguide that provides a luminous path 4045. The connection member 4040 canbe formed of or include a light reflective material or coated therewith.On the other hand, the heat dissipation unit 4030 can include heatdissipation fins 4031 and/or a heat dissipation fan 4033, and dissipatesheat generated upon operation of the light emitting diode 4010.

In this way, the light emitting diodes according to the embodiments ofthe present disclosure can be applied to headlights, particularly,headlights for vehicles, like the display device according to thisembodiment.

Although various exemplary embodiments of the present disclosure havebeen described hereinabove, the present disclosure is not limited to therespective exemplary embodiments and features described above.Modifications through combination and substitution of technical featuresdescribed in the exemplary embodiments are included in the scope of thepresent disclosure, and various modifications and alterations can bemade without departing from the spirit of the present disclosure asdefined in the claims.

1-23. (canceled)
 24. A light emitting device comprising: a lightemitting structure including a first conductive type semiconductorlayer, a second conductive type semiconductor layer, and an active layerdisposed between the first conductive type semiconductor layer and thesecond conductive type semiconductor layer; first and second contactelectrodes disposed over the light emitting structure, the first andsecond contact electrodes being in ohmic-contact with the first andsecond conductive type semiconductor layers, respectively; an insulatinglayer insulating the first and second contact electrodes from each otherand at least partially covering the first and second contact electrodes;and first and second electrodes disposed over the light emittingstructure, the first and second electrodes electrically connected to thefirst and second contact electrodes, respectively, wherein each of thefirst and second electrodes has a boundary such that a portion of theboundary of the first electrode faces a portion of the boundary of thesecond electrode; and the portion of the boundary of the first electrodeor the portion of the boundary of the second electrode comprises acurved shape along the boundary.
 25. The light emitting device of claim24, wherein a remaining portion of the boundary of the first electrodeor the second electrode has a curvature pattern different from thecurved shape.
 26. The light emitting device of claim 25, wherein thecurvature pattern has a reverse trapezodial sawtooth pattern, triangulasawtooth pattern, a trapezodial sawtooth pattern, or a rectangularsawtooth pattern.
 27. The light emitting device of claim 24, furthercomprising an insulation support disposed under the first and secondelectrodes to provide coupling regions for the first electrode and thesecond electrode.
 28. The light emitting device of claim 27, wherein theinsulation support has a portion with a curved shape corresponding tothe curved shape of the at least one of the first electrode or thesecond electrode.
 29. The light emitting device of claim 24, wherein thecurved shape includes a convex part having a width increasing in aprotrusion direction.
 30. The light emitting device of claim 24, whereinthe first electrode and the second electrode are spaced apart from eachother by a distance ranging from 30 to 300 μm.
 31. The light emittingdevice of claim 24, wherein the insulating layer includes multiplelayers.
 32. The light emitting device of claim 24, wherein theinsulating layer includes a distributed Bragg reflector.
 33. A lightemitting device comprising: a first conductive type semiconductor layer;a mesa structure formed over the first conductive type semiconductorlayer and including an active layer and a second conductive typesemiconductor layer; a first contact electrode formed over the firstconductive type semiconductor layer to make electrical contact with thefirst conductive type semiconductor layer; a second contact electrodeformed over the mesa structure to make electrical contact with thesecond conductive type semiconductor layer; a first insulation layerformed to cover the first contact electrode and the second contactelectrode and having openings that expose the first contact electrodeand the second contact electrode; a pad formed over the first insulationlayer to electrically contact with the first contact electrode and thesecond electrode through the openings; an insulation support formed overthe pad; a first electrode formed in the insulation support and havingan edge with a first pattern and a second pattern that have differentshapes from each other; and a second electrode formed in the insulationsupport and adjacent to the first electrode, and wherein the insulationsupport has an edge with a third pattern and a fourth pattern thatcorrespond to the first pattern and the second pattern, respectively.34. The light emitting device of claim 33, wherein the second electrodehas an edge with a fifth pattern and sixth pattern that correspond tothe first pattern and the second pattern, respectively.
 35. The lightemitting device of claim 33, wherein a portion of the edge of the firstelectrode that is adjacent to the second electrode comprises anarrangement of alternately arranged convex part and concave part. 36.The light emitting device of claim 35, wherein the convex part of theportion of the edge of the first electrode has a width increasing in aprotrusion direction.
 37. The light emitting device of claim 35, whereinthe convex part of the portion of the edge of the first electrodeoccupies at least a quarter or more of an entire area of the firstelectrode and the second electrode.
 38. The light emitting device ofclaim 33, wherein the first pattern comprises a sawtooth shape.
 39. Thelight emitting device of claim 33, wherein the second pattern comprisesa curved shape.
 40. The light emitting device of claim 33, wherein aportion of the edge with the second pattern is disposed on the firstinsulation layer.
 41. The light emitting device of claim 33, wherein thefirst insulation layer includes multiple layers.
 42. The light emittingdevice of claim 33, wherein the first insulation layer includes adistributed Bragg reflector.